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ASTRONOMICAL ESSAYS 



REV. GEORGE V. I.EAHY, S. T. Ju. 



ST. JOHN'S SEMINABY, BBIGHTON, MASS. 



Copyright secured 



BOSTON : 

WASHINGTON PRESS 

242 Dover Street 

1910 



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NIHIL OBSTAT. 

Joannes B. Peterson, 
Censor Deputatus. 



IMPRIMATUR. 

^ GULIELMUS, 

Archiepiscopus Bostoniensis. 



©CIA261792 






THIS VOLUME 

IS 

RESPECTFULLY DEDICATED 

TO THE 

MOST REV. WILLIAM H. O'CONNELL, D. D. 

Archbishop of Boston, 

under whose 

kindly auspices and encouragement 

IT WAS 
INITIATED AND BROUGHT TO COMPLETION 



"Why did not somebody teach me the constella- 
tions, and make me at home in the starry heavens, 
which are always overhead, and which I don't half 
know even to this day?" 

Thomas Carlyle. 



FOREWORD. 

This volume of astronomical essays has been com- 
piled from a series of articles originally published in 
the Boston Pilot over the pen-name of Catholicus. 
The series is here presented connectedly at the request 
of the Most Reverend Archbishop of Boston, who has 
graciously written the author, "I highly commend 
your articles on astronomy for publication in book 
form." 

A new book on the science of the heavens needs no 
apology. There will always be found many, like 
Carlyle, eager to learn more and more concerning the 
occupants ot the sky. Even to persons only moder- 
ately interested in nature, must occur from time to 
time certain pertinent questions. Some will be curious 
to learn of the distance of the heavenly bodies. How 
far from us are those gleaming lights ? Are they our 
near neighbors, as they appear to be, or are they, 
on the contrary, many miles away? Again, what of 
their size? Are they but shining disks and points, 
or are they perhaps globes comparable to our great 
earth? Others will ask of their physical condition, 
whether it is like or unlike that of the earth ? What 
is the purpose of their being? And, above all, do 
they show signs of possessing living occupants? 
These, and kindred questions, will find an answer 
in the following chapters, especial emphasis being 
given to the important subject of the habitability 
of the heavenly bodies. 

As will be observed , the series begins with a chapter 
on the shape of the earth. Some, reading the chapter, 



^ Foreword. 

may experience surprise that so much space has been 
allotted to a subject so simple and familiar. The 
topic has, however, been expanded advisedly, not only 
because it forms the starting-point of all astronomical 
inquiry, but because the fact of the earth's spherical 
shape is the initial wonder of the universe. Once 
we have realized that this great earth of ours is a 
globe set apart in space and suspended in mid-ether 
without support, with all that this signifies, we 
are prepared to accept the later affirmations that 
the earth is spinning on an axis and coursing through 
space about the sun. These and other cardinal 
truths of astronomy have undoubtedly long since 
become familiar. If the arguments in their favor 
are here set forth at considerable length, it is that 
the reader may know how firm are the fotmdations 
on which the science ot astronomy rests. 

Besides the purely scientific chapters, drawn from 
systematic astronomy, there are others of a more 
apologetic trend. Their general purpose is to prove 
that neither the Christian religion nor the Catholic 
Church is in any way opposed to the science of as- 
tronomy or to its progress. In this vein are the 
chapters on the Astronomy of the Bible, that of the 
Fathers, and that of the Middle Ages, subjects not 
often treated, and seldom, if ever, gathered into the 
same volume. The modem era is even richer in 
material of apologetic interest. That Catholics have 
done their full share for the advancement of astron- 
omy is set beyond doubt in the chapters on Copernicus, 
the Reform of the Calendar, and Recent Catholic 
Astronomers. 

The most important portions of the book are those 



Foreword. vn 

that deal with the Case of Galileo and the Nebular 
Hypothesis. Not only popularly, but apologetically, 
these topics are among all that have been selected 
the chief in interest. They are rocks of offense on 
which the faith of many has suffered shipwreck. 
Special care has therefore been given to the handling 
of these two themes. The effect of the presentation 
will be, it is hoped, to remove misconceptions, to 
confirm the strong in faith, and to reassure the 
wavering. 

Text-books on astronomy already abound. No 
better could be recommended to the interested reader 
than Newcomb's short Elements of Astronomy, 
published by the American Book Company. With 
this work and others of like character the present 
volume does not presume to enter into competition. 
It is meant rather as a book for general reading, 
for use in the library of one's home rather than for 
the school-room. Even as such, it has its limitations, 
of which the author is only too keenly conscious. 
He bespeaks it favor, nevertheless, because of the 
purpose it is intended to serve, the honor of God 
through the reverent study of the works of His 
creation. 

The author wishes to acknowledge gratefully his 
indebtedness to Mr. James P. Sherry, a student at 
the Boston Seminary, for the chapter on Galileo as 
a Physicist. 

Feast of the Resurrection, 1910. 



TABLE OF CONTENTvS. 



Chapter 

I. Shape of the Earth 

II. Relative Magnitude of Earth and Sun 

III. Rotation of the Earth . 

IV. Revolution of the Earth 

V. Nicholas Copernicus 

VI. The Planetary System . 

VII. Nature oi the Sun . 

VIII. Habitability of the Planets 

IX. The Planet Mars . 

X. Astronomy of the Sidereal World 

XI. Habitability of Remote Planets 

XII. The Bible and Astronomy . 

XIII. The Bible and Star- Worship 

XIV. The Miracle of Josue 

XV. The Fathers and Astronomy 

XVI. Astronomy in the Middle Ages 

XVII. Reform of the Calendar 

XVIII. Galileo as a Physicist 

XIX. The Condemnation of Galileo 

XX. Recent Catholic Astronomers 

XXI. Fr. Secchi. Later Astronomers 

XXII. The Nebular Hypothesis 

XXIII. Theory of Laplace . 

XXIV. The Nebular Hypothesis and Creation 

XXV. Summary and Conclusion 
Appendix — Tables and Laws . 



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145 

158 

170 

181 

189 

208 

219 

231 

241 

253 

260 

265 



IX 



PRAISE OF THE CREATOR. 

"The spacious firmament on high, 
With all the blue ethereal sky, 

And spangled heavens, a shining frame, 
Their great Original proclaim. 

"What though, in solemn silence, all 
Move round this dark terrestrial ball ; 

What though no real voice nor sound 
Amid their radiant orbs be found ; 

In Reason's ear they all rejoice, 
And utter forth a glorious voice. 

For ever singing as they shine, 
The hand that made us is divine.' " 

Joseph Addison. 



ASTRONOMICAL ESSAYS. 



CHAPTER I. 
THE SHAPE OF THE EARTH. 

Some people find it strange that a study of the 
earth should be included in the science of astronomy. 
Is not astronomy, they ask, the science of the stars 
and heavenly bodies? Now, they argue, the earth 
is not one of the heavenly bodies; it is not located 
in the sky, it is right here under our feet. How, 
then, and by what twisting of words can it be given 
a place in astronomy? 

And yet this globe of ours has its place in the 
science of the heavens and, indeed, a place of real 
importance. It would be anticipating too much to 
say thus early that our earth is a planet, like Venus 
and Jupiter and certain other bodies that are visible 
in the firmament. Before we are ready to accept this 
statement, much argument and proof will be needed. 
Told us in the beginning of our investigation, it is 
merely a vain assertion. But even from now and at 
the very inception of our studies, we can realize that 
the earth is the vantage-point from which alone it is 
given us to examine the myriads of lights that dot 
the heavens. 

1 



2 Shape of the Earth. 

The Earth Our Observatory. All our inspection 
of the celestial bodies, all our measurement and 
analysis of them, must start from the earth as our 
viewpoint and centre. It is truly our astronomical 
observatory, from which alone we can measure the 
sizes, angles, and distances of the objects that people 
the heavens. Hence, before we can learn anything 
definite about the sun, the moon, and the stars, we 
have to understand our own earth and, above all, we 
need an accurate knowledge of its shape and size. 
If we start with a wrong conception of these, we 
shall be betrayed into innumerable errors regarding 
all astral bodies. This is the justification for begin- 
ning the present series of astronomical sketches with 
a chapter on the true shape of the earth. 

Belief of the Ancients. All primitive peoples 
thought of the earth's surface as a flat, level 
plain, roughened, it is true, by hills and moun- 
tains and indented by valleys and ravines, but 
still in its larger aspects a level, horizontal 
expanse of land and sea. Indeed, is not this 
its obvious appearance? From any single post 
of observation, even if it be a mountain-top or the 
ocean with its unimpeded view, who would doubt that 
the earth is level, who would infer that it slopes away 
in the form of a curve? Even today there are some 
persons, — and we need not go beyond Boston to 
find them, — who still proclaim their belief in the 
flatness of the earth. We may charge them with 
being crassly ignorant. But how should we set about 
to refute them? The simple testimony of the senses 
seems to say that the earth is level. I may ride for a 
thousand miles in a railroad train from Boston to 



Shape of the Earth. 3 

Chicago and except for the sHght upgrades and down- 
grades due to intervening mountain slopes, I shall 
certainly think that I have been following a dead 
level line. Or I may cross the Atlantic in an ocean 
liner and in that long journey of three thousand 
miles never once realize that I am being borne around 
the surface of a sphere. Whether on land or sea, the 
earth seems a plain, and if I trust only to first ap- 
pearances, I shall pronounce it such. 

It must not surprise us, then, to learn that of old 
all men, even the wisest, conceived the earth's surface 
as a level plain. In the olden times, in the morning 
of the history of the race, people did not travel as 
readily as now; they had no cars or boats propelled 
by steam or electricity to whirl them from one place 
to another. They had for means of travel only their 
limbs, and beasts of burden like the camel and the 
horse. To voyage a hundred miles was for them a 
serious journey. They sojourned but little in foreign 
lands and among strange peoples, and in turn few 
strangers came among them. And when strangers 
did arrive from the distance of a few hundred miles 
they were said to have come from afar. 

Geography of the Jews. How small, for example, 
was the portion of the earth's surface known to the 
early Hebrews! Their knowledge of geography was 
limited to the southwestern corner of Asia and the 
northeastern corner of Africa. Besides Palestine, 
the land of the promise, they knew of countries to the 
north verging towards the present Black Sea, of Egypt 
and Arabia to the south, and of Mesopotamia to the 
east. How narrow the boundaries that encompassed 
the then known earth! The Black Sea, the Mediter- 



4 Shape of the Earth. 

ranean, the Nile River, a line stretched across Arabia 
from the upper Red Sea, and the Euphrates River 
to the east, these formed very nearly the uttermost 
boundaries of the earth as it was known to the ancient 
Jews. In this space were included only three bodies 
of water of considerable size, the Red Sea, the Dead 
Sea, and the Mediterranean, and of the latter they had 
explored only the eastern end. 

With such limited knowledge (for which, however, 
to blame them would be puerile), how natural it was 
that they should think of the earth's upper surface as 
perfectly level. How far it stretched they did not 
know, and said no man could know. But wherever 
it ended, it took the form of a vast horizontal 
circle, and on this circular rim was supported 
the great vault of the sky. Down under the 
earth's surface were subterranean basins for supplying 
the rivers and oceans, and lower yet were what they 
called the great abysses, of unfathomable depth. 

Jews' Superiority of Concept. Undoubtedly all 
early peoples had some such notion of the earth's shape 
and structure as had the Hebrews. If the question 
occurred to them what it was that supported this 
immense earth and held it up, they answered 
variously according to their lights and fancies. Most 
primitive peoples, as even the lettered Hindus and the 
cultured Greeks, thought fantastically of some 
monstrous elephant or of some giant Atlas supporting 
the world upon his shoulders. To the credit of the 
Hebrews be it said that they avoided all such myths 
and childish fantasies, attributing the upholding of all 
things to the word of God's power (Heb. i, 3). It was 
God who had set up the pillars of the earth (Ps. Ixxiv, 



Shape of the Earth. 5 

3). "He stretcheth the north over the empty place, 
and hangeth the earth upon nothing," such was the 
sublime and daring thought of the Book of Job 
(xxvi, 7) , one of the many true and exalted concepts 
that lift the Hebrew Scriptures above the writings of 
every other primitive people. 

PTOLEMY'S STUDY OF THE QUESTION. 

The first man who proved clearly that the earth is a 
globe was Ptolemy, the illustrious Grecian astronomer 
of the second century of the Christian era. When we 
read his arguments, we see that, as far as they extend, 
they are just as convincing as are our proofs of today. 

Ptolemy's First Argument. Consider, for example, 
his argument of the manner in which a ship disap- 
pears as it recedes from the shore. If it were riding 
on a level, it would disappear from sight all at once, 
at the moment when our power of sight was now too 
feeble to follow it. But, as a matter of fact, it sinks 
from sight as if it were being swallowed up in a trough. 
The hull of the vessel disappears first, declining below 
the water's edge, but for some time after we may still 
see the decks, the masts, and the sails. These then 
disappear in the order of their height, the topmast and 
its sails last of all. To all appearances the ship has 
been gradually submerged. But were we on the ship 
instead of on the shore, we should still find our craft 
riding the waves in safety. 

The only possible explanation of the gradual dis- 
appearance of the vessel part by part, is that she has 
been following not a horizontal line but a line bent 
away from the horizontal in the form of a continuous 



6 Shape of the Earth. 

curve, and that in this instance at least the ocean's 
surface is not level but curvilinear. The observations 
of Ptolemy made at Alexandria in Egypt eighteen 
hundred years ago, can be easily repeated by us in 
Boston Harbor or Massachusetts Bay in the present 
year of grace and with the same results. Indeed they 
can be repeated on any and every ocean, sea, or large 
lake throughout the world. The earth, then, is nowhere 
fiat as its first appearance indicates, but everywhere 
slopes away from a level in the form of a circular arc. 

Argument from the Stars. Ptolemy's second argu- 
ment, though not so simple, is however equally cogent. 
It rests on the change in our starry heavens as we 
alter our position on the earth to some different degree 
of latitude. As we move to the southward, for ex- 
ample, particularly if our journey covers many miles, 
new stars and constellations appear above our south- 
ern horizon and the old ones are displaced. From 
Boston we are never privileged to behold such brilliant 
constellations as the Centaur and the Southern Cross. 
But let us travel southward to the Tropic Zone, then 
these glittering groups of southern stars will rise above 
the margin of the sky. 

It must be that our southern horizon has been 
depressed so low as no longer to act as a screen between 
us and them. Were the earth level, the horizon 
would hold its direction and position relative to us and 
these southern stars, and would continue to conceal 
them from our view. To the earlier readers of 
Ptolemy this argument meant more than it does to 
most of us. For in his time people made a practice 
of observing and studying the stars, and were quite 
familiar with their names and groupings. Among 



Shape of the Earth. 7 

the city-bred people of modern times there are very 
few who watch the stars and come to know their names 
and relative positions. The more's the pity, for they 
thus remain in ignorance of the details of that wonder- 
ful design which the Creator has imprinted on the 
heavens. 

After Ptolemy. In view of the undoubted cogency 
of Ptolemy's twofold argument, how came it, we may 
ask, that in the Middle Ages so many doubted the 
sphericity of the earth, continuing to believe that its 
upper surface formed a level plain? Arguments from 
the Hebrew writings and a misunderstanding of their 
scope undoubtedly had some effect in counterbalanc- 
ing the weight of Ptolemy's reasoning. There was 
moreover the apparently clear testimony of the senses 
that the earth is a fiat body and not round. So 
throughout the medieval period some inclined to one 
belief and some to its opposite. It was a period of 
uncertainty as far as this particular problem was con- 
cerned, and the uncertainty was not finally dispelled 
till in the year 1521 the crew of Magellan, the Portu- 
guese Catholic, accomplished the circumnavigation of 
the globe. 

PRESENT LISTING OF THE ARGUMENTS. 

In our present manuals of astronomy many separate 
lines of argument are traced, each going to show that 
the earth is of spherical form. Among these the four 
most striking may be summarily indicated as follows : 
First there is given Ptolemy's argument from the 
manner of a ship's disappearance at sea, as developed 
above. 



8 Shape of the Earth. 

Eclipses of the Moon. Secondly, eclipses of the 
moon afford a new ground for the inference that the 
earth's shape is spherical. Not infrequently, as a rule 
once or twice in every year, the full moon is eclipsed 
either wholly or in part by passing into the shadow 
of the earth. That it is the earth's shadow which 
causes the eclipse, there is not the slightest room for 
doubt. In every lunar eclipse then, we can witness 
the earth's shadow projected on the moon's surface 
just as truly as in other circumstances we can observe 
on the ground the shadow of a tree or building. 

Now the shadow on the moon is always a circle or 
the segment of a circle, and this holds true for all 
eclipses no matter in what direction from the earth 
the moon be placed, whether over the eastern or the 
western hemisphere. From this it follows that the 
boundary of the earth is in its every part of circular 
form. For a shadow reproduces correctly the 
outline of the original as we plainly see in the case of a 
tree or building. We conclude, therefore, that if the 
earth's shadow is circular its boundary and contour 
must be circular also. And the only possible form 
of an object that will appear circular from whatever 
side it be viewed is the globular or spherical. 

Analogy With the Heavenly Bodies. A third ar- 
gument for the sphericity of the earth is that derived 
from analogy with the heavenly bodies. We know 
that the sun is a globe and that the moon is one as 
well. So, too, the planets. Mercury, Venus, Mars, and 
the rest, when viewed through a telescope, are seen 
to be quite evidently of spherical figure. Indeed 
the spherical is the usual and perhaps the universal 
form in inanimate nature, if the larger bodies alone 



Shape of the Earth. 9 

be considered. By analogy we should infer that our 
earth also is a globe. For in nature throughout its 
length and breadth all things follow common laws. 
Their unity of structure is indeed a proof of the unity 
of their Creator. 

Circumnavigation of the Globe. Fourthly and 
finally, the earth is proved to be a sphere by the fact 
that it has been sailed around, first by the crew of 
Magellan, the Catholic, in the memorable voyage 
lasting from 1519 to 1521. Parenthetically it may 
be interesting to us of the United States to learn that 
this daring expedition of discovery was halted for a 
long time in the Philippine Islands and there, in a 
land now our colonial possession, Magellan himself, 
the commander, went to his death and lies buried. 
Many times since and in many different directions 
has the earth been circumnavigated, so that there is 
now abundance of observational proof as well as 
argument of mere reasoning to convince us that the 
earth is round. 

Why Not Accepted Earlier? Once more may occur to 
us the wonder that the true shape of the earth was not 
earlier recognized. For it is now one of the most 
patent facts of science. But transporting ourselves 
back to the Middle Ages, we may easily realize how 
the above arguments failed of their effect. The 
fourth argument was not yet available. Till Columbus 
crossed the Atlantic, Europeans knew of no hemi- 
sphere other than their own. To the west and to the 
far east all was mystery. The first argument, that 
of Ptolemy, was well enough for determined localities. 
But who would assure the earlier people that the 
asserted phenomenon would hold good at every sea- 



10 Shape of the Earth. 

coast and every lake-border? It was an argument 
from induction and the induction was not yet suffi- 
ciently complete. 

The argument derived from eclipses of the moon 
was probably never offered for their consideration, 
surely not with all its present force. Lunar eclipses 
were for them mysterious phenomena, attributed by 
some indeed to supernatural causes; and they 
would find it hard to believe that the shadow of the 
great earth could be so diminished as barely to cover 
the face of the moon. Finally the spherical figure 
of sun, moon and planets, even if fully assured to 
them, would scarcely suggest to their minds that the 
earth must have a corresponding form. For the 
heavenly bodies were placed by them in one category, 
the earth in another. The former were ethereal 
objects of strange substance moving lightly in the 
upper atmosphere; the earth was terrestrial, made 
not of fire but of land and water, God's footstool and 
the centre of the universe. 

For all these reasons the world for centuries doubted 
or stood divided between two opposite opinions, one 
that of Ptolemy, founded on rational argument and 
asserting the rotundity of the earth, the other 
founded on sensible appearances and maintaining 
that at least the upper and habitable surface of the 
earth forms a level plain. 

Conclusion. And now if a sceptic approaches you, 
young scholar, on Boston Common or elsewhere, 
and argues that the earth is not round like the globe 
in your schoolroom but flat like the maps in your 
geography, perhaps you will be able to refute him. 
Tell him of the ship disappearing part by part below 



Shape of the Earth. 11 

the horizon; tell him of the earth's circular shadow 
that covers the disk of the moon; point out to him 
the sun and moon and planets and let him say if these 
are not rounded bodies, and remind him of Magellan's 
trip around the globe. Submit to him finally that 
his error has been to mistake appearances for reality. 
"Things are seldom what they seem." Reason must 
ever be invoked to correct the misleading evidence 
of the senses. And in no department of knowledge 
will this correction be more often necessary than in 
the science of astronomy. For this in part has God 
given to man the noble faculty of reason. And it 
has been a part of God's providential plan, so proves 
the history of thought, to establish the worth of 
reason by guiding it gradually to a fuller knowledge of 
His visible creation. 



CHAPTER II. 
RELATIVE MAGNITUDE OF EARTH AND SUN. 

In the panorama of the heavens as witnessed from 
the earth, the most impressive single object is un- 
doubtedly the sun. Of all celestial bodies it is, 
or at least appears to us, the largest and the bright- 
est. It makes our day and creates our seasons. 
When it shines, it dominates the heavens, putting 
to flight the other heavenly bodies almost without 
exception. In the starry realms it is the sun that 
seems to reign supreme. Supreme, therefore, must 
be its place in the science of astronomy. What 
sort of body is this brilliant orb, what is its distance 
from the earth and how great its size, these are 
evidently among the very first questions that astron- 
omy must, if possible, answer. 

In our present inquiry let us select for consideration 
the last-mentioned of these problems, that, namely, 
of the sun's volume or magnitude. Comparing sun 
with earth, let us seek to learn which is the larger 
body of the two, and whether they are almost alike 
or on the contrary far apart in size. 

The Seeming Answer. At first view the answer to 
these queries seems ridiculously easy. For while the 
sun is evidently the mightiest of the heavenly bodies, 
when compared with the earth it seems to sink to a 

12 



Size of Earth and Sun. 13 

place of insignificance. Is it not after all merely a 
light, brilliant and resplendent and dazzling, to be 
sure, but still a mere disk of light, so small that with 
our vision we can compass it all at once from end to 
end? Brightest of luminaries, yes, and yet so far 
from filling the sky that it would take hundreds of 
similar disks to cover the heavens even along one 
line. 

MAGNITUDE OF THE EARTH. 

And now behold under the sky this earth of ours, 
broad, expansive and seemingly unconfined, to all 
appearances as spacious in length and breadth as the 
firmament itself! With this wide earth, who thinks 
of comparing that narrow circle of light? It seems 
to me that could I seize that luminous ring and draw 
it down, I might find space for it on a certain round 
table in my dining hall. 

Comparison Seems Absurd. Compare the sun's 
size and the earth's — someone is heard to say con- 
temptuously — the very idea is preposterous. For 
do I not know that it takes days and days to travel 
from one coast of our continent to the other, even by 
the fastest express, and that to cross the succeeding 
ocean demands another week or even weeks? And 
do there not remain other continents to traverse 
broader than our own, and a second ocean to cross 
before home is reached again? Perhaps Jules Verne 
was not far from right in his guess when he chose 
as title for one of his fanciful stories, "Round the 
World in Eighty Days." Journey a little away 
from this favored city that we smugly call the Hub, 
and we shall learn to our confusion of what tiny 



14 Size of Earth and Sun. 

dimensions it is when compared with the entire 
wheel's vast circumference. 

And yet through all our journeyings the sun grows 
no larger. It remains forever the same small disk 
of light, only a millstone in breadth, and we could find 
many a nook and comer of this great world that we 
call the earth where it could be tucked away and 
made to sink from sight. 

True Greatness of the Earth. Such is the verdict 
we arrive at if we trust to appearances alone. And 
respecting one of the two bodies compared our verdict 
is correct and stands justified by the facts. The 
earth, our residence, is indeed a body of no mean 
dimensions. It is by itself a world, a universe, 
spacious enough to accommodate with room to spare 
the thousands of millions of human beings who now 
inhabit it, vast enough to have been the sole theatre 
of action for all the myriad events of human history. 

Once on a time its western boundaries were the 
pillars of Hercules towering above Gibraltar's straits. 
Then they were moved farther on, to San Salvador, 
and later to the Golden Gate of the Pacific Coast. 
Then they advanced six thousand miles across an 
island-dotted ocean to the rich empire of Japan. 
Only then had far Cathay been reached from the east 
which Marco Polo in the thirteenth century had 
reached overland from the west. West and east had 
met and were one. 

Earth's Greatness and Our Littleness. The globe 
had been encircled and what a mighty sphere it was ! 
25,000 miles in extent its girdle, so the measure- 
ments told us, and its diameter through the earth's 
centre, from rim to rim, a round 8,000 miles. Our 



Size of Earth and Sun. 15 

deepest mines, our profoundest excavations, scarcely 
exceed one mile. Shall ever the remainder of the 
vast interior be explored? We skim the surface, 
we make here and there a dent, and we fondly think 
we have completed the exploration of the earth and 
have nothing more to learn. But now and then an 
earthquake or a volcanic blast rends the crust and 
confounds the littleness of our science. Mother 
Earth reveals her own immensity. Yes, such is the 
earth, a mighty body, constructed on a scale so vast 
that nature's most awful cataclysms cause her no 
lasting injury, but leave her stable as before. When 
the fiery storm has passed, she can still boast her 
unshaken continents and her everlasting hills. 

The Sun a Rival in Greatness? But high above the 
earth shines on the refulgent sun. He, too, is ever- 
lasting, is he not, like the earth in his age and in his 
youthfulness. The same luminary that shines on 
us lit up the earth for our remotest ancestors. And 
ages before they came, in the dim past when only 
vegetative life clothed and peopled the earth, the 
sun was already at his post sustaining the life which, 
without him, must have perished. Sustaining, did 
we say? Is it then true that our earth owes such 
dependence to the sun? Can it be possible after all 
that the sun is the more important and the mightier 
body of the two? Wait and we shall see. 

EARTH'S DEPENDENCE ON THE SUN. 

It needs but little observation to tell us that the 
earth depends upon the sun in many different ways. 
Even the most casual and inattentive of observers 



16 Size of Earth and Sun. 

can see that the sun is our greatest natural source of 
light and heat, and the essential condition of all 
terrestrial life. It is truly the agent set in the heavens 
by the Creator for supplying the earth with warmth 
and light, and the requisites of life. It is at once the 
light-giving and the heat-giving body, and the life- 
giving body as well, if life be taken merely as a phy sical 
phenomenon. 

Exaggerations of the Ancients. Inevitable it was 
that from the very beginning men should look up at 
this great luminary in wonder and admiration. And 
not unnatural was it for the superstitious heathen 
people of old to adore it as a god, one of the most 
powerful, indeed, and one of the most beneficent in all 
their Pantheon. Every day this mighty deity drove 
his fiery chariot across the sky, and before it darkness 
was dispelled, clouds and mists were rent asunder, 
and the host of the stars was put to rout. Once an 
ambitious youth named Phaethon essayed to enter 
this fiery chariot, to take the reins and drive the horses 
of the sun. But he paid for his rashness, so runs the 
legend, with his death. 

Not as a divinity would I picture to you the sun, 
no more than I would deify an electric light, or a 
raging furnace-fire used to light and warm and 
animate all parts of some large factory. But with 
the ancients I would still picture the sun as a huge 
ball of fire, whose size and power are greater by far 
than casual observation would lead us to believe. 

Prodigality of the Sun*s Light. Think of the amount 
of light and heat that the earth receives from the 
sun. It comes to us in quantities that are prodigal. 
Over an entire hemisphere of this vast earth it shines 



Size of Earth and Sun. 17 

at once, illuminating all parts almost equally. Were 
electric arc lights substituted in its stead, they would 
have to be placed as thick as the leaves of the forest, 
and even then they might not suffice. 

A Bessemer furnace of molten steel is, they tell us, 
the most dazzling of all artificial lights. In its 
presence not only strangers, but even the workmen 
accustomed to its glare, have to shield their eyes with 
smoked or colored glasses for fear of being blinded. 
Yet measurements of comparison have been made, 
which inform us that the light of the sun even as it 
reaches us after travelling an unimaginable space, 
is five thousand times more intense than that of the 
white glowing mass of molten steel. So superior is 
the solar orb to all, even the brightest, illuminants 
devised by man. 

Beauty of the Sunlight. How rich and glorious 
indeed is the light of the sun! How cheerfully it 
slants across the earth on a clear, cold winter's day, 
making the very atmosphere luminous, brightening 
earth and sky and the air that lies between! Even 
through thick banks of cloud which no other light can 
penetrate, some of the sunlight makes its way, 
enough and more than enough to enable me to pursue 
this writing. And for an hour or more after the sun 
has set, its second light, its twilight, is still in evidence, 
painting in gorgeous colors the western sky. 

And when twilight has gone and darkness super- 
venes, how we miss our great luminary! O Earth, 
thou art dark and black and helpless now; thou hast 
no native source of light on which thy inhabitants 
can rely. We go groping about with tapers made 
to emulate the sun, and with difficulty we find our 



18 Size of Earth and Sun. 

way. But patience, only a few hours must we wait. 
Let us look towards the east, and keep in hope our 
darksome vigil. Only a few hours and then, lo! the 
rosy tints in the eastern sky betokening the Morn! 
So great a being cannot enter unannounced. He 
must have his advance guard in the form of rosy 
streamers and banks and clouds of color. And when 
the guards in orderly and brilliant array have passed 
to their places, then comes the sun, their chief, calm 
and serene, resplendent and effulgent, his luminosity 
unaltered and undiminished, his power as great as 
yesterday and as on a million yesterdays ! 

Source of the Sun's Power. Effects as great as these 
that have been described require an adequate cause. 
There must be something to explain the wide abundant 
stream of light that passes unceasingly between sun 
and earth, and those other floods that are radiated 
from the sun in all directions, most of them to be 
lost in space. To duplicate only that fraction of the 
sunlight which the earth receives, what enormous 
furnace-fires we should have to enkindle, what hosts 
of electric lamps animated by a million dynamos! 
Of what immensity, then, must be the sun's furnace- 
fires and dynamos or whatever corresponds to these! 
The sun is indeed a great globe of fire, huge in size, 
all alive with physical energy, only a small part of 
whose output is employed by nature to illuminate the 
earth. 

Other Benefactions. Thus far we have seen to what 
degree the earth is indebted to the sun for the in- 
valuable gift of light. Now let us emphasize the ad- 
ditional fact that we receive heat from the sun as well 
as light, and in corresponding measure. 



Size of Earth and Sun. 19 

A very little reflection will convince us that the 
earth does not contain within itself the adequate 
source of the warmth it manifests. True it is that the 
globe's interior is much hotter than the surface, as 
volcanos and geysers and other similar phenomena 
testify. But that this internal heat is not sufficient 
to maintain at the surface an equable degree of 
temperature, is evident from the icy cold that attacks 
the polar regions when the sun's heat is temporarily 
withdrawn. It is not the interior fires of the earth 
but the radiant energy of the sun that brings to pass 
our prevalent genial climate. 

Effect of Sun's Untempered Heat. Instead of going 
into the figures given to express the quantity of heat 
that the sun lavishes on the earth, let us rather 
institute a contrast. Think first what would be our 
condition if there were no clouds, and above all no 
night to mitigate the ardor of the sun's rays. Suppose, 
moreover, that these rays descended not only in- 
cessantly but vertically downward upon some one 
portion of the earth. 

From the discomfort we now experience on an 
extremely torrid day we may argue the result. Is it 
not probable that in the circumstances supposed, 
every bit of plant life would be parched and burned to 
a crisp, and that even great forest fires would be en- 
kindled that would sweep unconquerably over the 
face of the globe ? 

Effect of Its Complete Withdrawal. Meantime, on 
the opposite side of the earth would reign perpetual 
night, with its necessary attendants of cold and gloom. 
Withdraw entirely the heat influence of the sun, and in 
a short time the oceans, wide and fathomless as they 



20 Size of Earth and Sun. 

are, would be frozen throughout their whole expanse 
and to their lowest depths. Such imaginary pictures 
teach us, perhaps better than mere figures could, the 
extent to which the earth is indebted to the sun for 
the warmth that prevails at its surface. Happily for 
us, both pictures are imaginary. A wise and bene- 
ficent Providence, employing the sun as His agent, 
gives to the earth that mean of heat which makes of 
it a habitable world. 

Sun a Life-Sustaining Agent. Not only for light 
and heat is our globe dependent on the sun, but for 
vital force as well. Observe how, when winter comes, 
the vegetative world is doomed to death or a state 
that simulates death. And winter means not that 
all the sun's assistance is withdrawn from the earth, 
but only a part of it, probably less than half. The 
days are shorter and the sun's rays reach us more 
obliquely. We suffer only a diminution of the solar 
influence, not its complete extinction. 

But even this partial loss is enough to cause in the 
vegetative world the semblance of death. The sap 
is frozen in the veins, no new leaves are born now, 
even in the evergreen trees, still less is there blossom, 
new fruit and seed. All plant life is stagnant, till 
the sun mounting higher in the heavens and lengthen- 
ing the days ushers in the spring. 

Loss Felt by Animal World. Meantime animal life, 
too, feels in its veins the benumbing influence of the 
sun's partial withdrawal, and some succumb, the old 
and the infirm. But the majority contrive to survive 
the winter's rigors, for animal exercise keeps the 
blood acoursing, and their strong nature is fitted to 
endure the partial withdrawal of the sun's helpful 



Size of Earth and Sun. 21 

influence. But let winter be prolonged everlastingly 
and with all its polar bitterness, what plant-seed 
could survive, what animal could endure? And let 
the sun's life-giving rays be taken from us, not partially 
but wholly, who shall calculate how short the time 
before the earth would be left barren and destitute of 
life? A few months only at the most would pass 
before every living being whose life is merely physical 
would sink into an eternal sleep that should know no 
awakening. 

Abundance of Terrestrial Life. So absolutely is 
terrestrial life conditional on the continuance of the 
sun's benign assistance. When now we think of the 
redundancy and plethora of earthly life, its all but 
countless forms and in its every form its all but count- 
less members, then we begin to realize the weight of 
the earth's indebtedness to the sun. And then there 
begins to come home to us a realization of the stupen- 
dous, mysterious power that the sun contains. 

Even now not all the gifts have been mentioned 
for which the earth is debtor to the sun. But enough 
has been established for the purpose of our argument. 
A summing-up would evidence that except for the aid 
of the sun, the earth would be without light, without 
appreciable warmth, and in its every region without 
life. Shall we still estimate the volume of the sun 
as that of some fire-balloon hung in the sky? Can we 
any longer believe it inferior to the earth in size? 

The Argument. Not from one body to its equal 
goes out such influence so steadily maintained. 
From higher to lower temperatures heat always flows, 
from more luminous objects to less luminous proceeds 
the light. To warm and illumine and vivify the earth 



22 Size of Earth and Sun. 

in the manner that actually obtains, to do this even 
for a single day, would require a globe paralleling the 
earth in size. To accomplish this indefinitely without 
cessation requires a globe immensely larger to serve 
as the sufficient storehouse for the needed energy. 
All the more as these same mighty influences are not 
directed towards the earth alone, but sent out in all 
directions to all the planets and to the emptiest parts 
of space. 

Thus from purely descriptive considerations, we 
are made ready to accept the figures that astronomers 
give for the diameter and volume of the sun. They 
have measured for us this great orb, as they have 
measured the earth. And they tell us that in diam- 
eter it exceeds our planet more than a hundredfold 
and that its volume is great enough to encompass 
more than a million earths.* Such is the vastness 
of its scale ; such is its superiority of magnitude over 
the terrestrial sphere. Only such preponderance of 
mass and volume could account for the dominance 
it exercises. 

Conclusion. And now let us reverse our first 
judgment founded on the appearances of things. 
Scepticism aside, for it is unreasonable, let us acknow- 
ledge the sun incomparably the greater of the two 
globes, and our earth a ball of relatively insignificant 
size, small enough, indeed, to be tucked away in 
some corner of the sun and lost to view. 

But, wonderful to relate, the greater body waits 
upon the lesser. The sun serves the earth rather than 
the earth the sun, as all our argument has demon - 

* See Appendix. 



Size of Earth and Sun. 23 

strated. For the lesser globe it is that has been 
designed to be the residence of man. And in man 
are faculties and forces of a quality indescribably 
above all that the sun displays. The light of his 
intellect is superior to the light of the sun, the energy 
of will-power to the energy of heat. And the physical 
life which alone the sun can foster is surpassed beyond 
comparison by the spirtual life that is every man's 
birthright. Of more consequence than the sun, or 
than sun, moon and stars combined into this material 
fabric we call the world, is any and every human being 
"made in the image and likeness of God." 



CHAPTER III. 
THE ROTATION OF THE EARTH. 

Nothing perhaps has ever given us a greater 
shock of surprise than when we were informed for 
the first time of the daily rotary movement of the 
earth. Years ago some teacher in a class of physi- 
cal geography told us of it, and when he or she de- 
scribed the rotation of the earth, we rubbed our 
eyes in wonder. 

Even now there are, perhaps, some who have not 
yet recovered from their first shock of surprise and 
and still shake their heads in doubt when it is affirmed 
that this great globe of ours turns round upon its 
axis once every day. True, the assertion of the earth's 
rotation is made again and again, but asserting a 
thing does not make it so. As rational beings we 
should examine for ourselves this cardinal point in 
astronomical science to learn on what groimds it rests. 
Incidentally we shall learn that it was a Catholic 
priest who first revealed it to the world of scholars. 

ARGUMENTS AGAINST ROTATION. 

Earth's Apparent Repose. The first evidences at 
hand are all of them, everyone must admit, against 
the supposition of the earth's rotation. For barring 
superficial changes of relatively slight account, we see 

24 



Rotation of the Earth. 25 

in the earth no sign of motion whatever. The earth 
is so firm and stable that we are disposed to take it 
as the symbol of perfect repose. 

If there is one thing in nature that seems to be at 
rest in space, that object is the earth. We see animals 
and men flitting about on its surface, trains and other 
vehicles rushing nervously hither and thither, and 
vessels driven by wind or steam ploughing the deep. 
But the ground beneath our feet seems firm and 
motionless and we call it so ; and the oceans, though 
restless, remain confined within their allotted borders. 
If the earth itself is hurrying on, why do not buildings 
topple over and fall, especially those sky-scrapers 
that seem poised in such unstable equilibrium? 

Swiftness of Its Asserted Motion. And yet we are 
asked to believe that the earth is not only in motion 
but in such rapid movement as no locomotive could 
ever hope to rival. Though but plain men in the 
street, we can handle the figures involved as well as 
could the most advanced mathematician or astron- 
omer. For the assertion made is that the earth 
turns completely round upon its axis once in every 
twenty-four hours. And both astronomers and we 
agree that the equator of the earth measures 25,000 
miles. Now all this means that if my station is on 
the equator, as at Quito in South America, I am being 
whirled through a circle of 25,000 miles in every 
twenty-four hours, that is, at an average speed of over 
a thousand miles an hour. Is it possible that I can be 
hurried along at such tremendous velocity and have 
no consciousness of it? 

Granted that the speed will be somewhat less at 
my actual station here in Boston, the rate being re- 



26 Rotation of the Earth. 

duced about one-half, there still remains a velocity of 
five hundred miles an hour, and in some way I 
contend, still sceptic that I am, that this swiftness 
of motion ought to make itself perceptible. 

Ptolemy's Objection. Moreover if it were true that 
the earth is circling about so swiftly, would not its 
atmosphere be left behind, and as we tore our way 
through it, would there not result a constant and 
terrific hurricane that whould sweep the earth clean? 
A speed of one thousand or five hundred miles an 
hour would seem to necessitate a contrary wind of 
parallel velocity. Except the houses built on rock, 
what objects at the surface could withstand the 
force of so violent a tempest? 

Ptolemy it was, was it not, who first suggested this 
argument of "the great wind," and did not his argu- 
ment continue unrefuted throughout the Middle Ages ? 
I will stick to Ptolemy, so concludes the average man, 
and believe with him that the earth is a motionless 
sphere. For all the evidence of my senses and my 
reason points that way and I will need powerful argu- 
ments to convince me of the contrary. 

The Other Side. . So runs the plea for the defense, 
sounding so plausible that the jurymen make up their 
minds at once what their verdict shall be. But 
suddenly the plaintiff's lawyer, in this case Copernicus, 
a Catholic priest, begins his brief, with his first word 
unsettles the equanimity of the innocent jurymen, 
and proceeds with steadily increasing power to per- 
suade them of the falsity of his opponent's reasoning. 
Like the innocent jurymen we also must listen to him 
and strive to keep pace with him as he delivers bis 
plea. 



Rotation of the Earth. 27 



ARGUMENTS FOR ROTATION. 

Motion Not Self-Revealing. The argument for the 
rotation of the earth starts from the perfectly certain 
though somewhat elusive fact that motion never 
reveals itself directly. Motion is one of the few 
things in nature that have no voice and deliver no 
message. If I set myself in motion I am made aware 
of it, to be sure, by the exercise of my own muscular 
activity. But if without my effort I am borne along 
quietly and without jar or commotion, it can easily 
happen that I shall be absolutely unconscious of my 
forward movement in space. 

Let me suppose, for example, that I am a passenger 
on the Empire State Express, which makes the trip 
between New York and Buffalo in the short interval 
of eight hours. Many a time in this journey the train 
will be bowling along at the rate of more than sixty 
miles an hour. But I converse and read my paper 
and eat my noonday meal aboard the swiftly moving 
train with almost the same degree of comfort as if 
I were pursuing the same occupations in my room at 
home. 

Along level stretches of track the illusion is complet- 
est. Make the motion smooth enough, how swift 
soever it be, I, a traveller, will experience the same 
sensation of repose as if the train were standing still. 
Only by looking out of the car window and witnessing 
trees and poles and signal towers dashing by, do I wake 
to a sense of my exceedingly rapid flight. 

Illusion on the Sea. The illusion is even more com- 
plete aboard an ocean steamer. For the yielding waters 
beget less friction than do the steel rails. If I stand 



28 Rotation of the Earth. 

on deck in full view of the water, I can then, to be sure, 
behold the churning of the water at the prow and the 
waves rushing niadly by in precipitous flight, and if 
I keep my wits about me I may infer correctly that 
it is I that am moving and not the waves. But let 
me go below and sit in some cabin where no view of 
the ocean is possible, then shall I not only have no 
sensible evidence that the vessel is moving forward, 
but if I am suddenly asked in what direction we are 
travelling I may easily point the wrong way. Yet all 
the time the steamer is making twenty knots, and in 
one direction only. 

The Argument. Illustrations like these prove how 
powerless motion is to reveal itself directly. Irregular, 
interrupted, jarring motion, this indeed has the power 
of making itself known. For when the speed is 
checked I topple forward, and when it is suddenly in- 
creased I am thrown backward. But if the motion 
is perfect, if it is made regular and uniform and with- 
out change in amount or direction, then other things 
may tell me of it, but the motion itself never will. 

And now perhaps we can understand why we have 
no sensible direct evidence of the earth's rotation. 
Grant for the sake of argument that the earth is rotat- 
ing even at high speed, with only the proviso that the 
speed is well-regulated and uniform, by no possibility 
can I feel its motion nor will there be given me any 
direct evidence of it whatsoever. 

Indirect Evidence. It is not to direct evidence but 
to indirect that we must turn for the proofs that in 
the earth there is a movement of rotation. The 
answer to the question of the earth's rotary motion 
is to be read, not in the earth itself, but in the stars 
and sky. 



Rotation of the Earth. 29 

Everyone knows that the sun appears to revolve 
about the earth as a centre once in every twenty-four 
hours. Its rising, culmination, and setting are so 
many incidents in its daily round. Nearly all have 
observed also that the moon traces a similar orbit, 
though its journey occupies a somewhat longer time. 
And they that watch the stars from hour to hour of the 
night have learned that they too rise, culminate, and 
set as do the sun and moon, and in approximately 
the same time. Viewed as a unit, the heavens above 
present the spectacle of a massive sphere turning on 
an axis in a period of one day. From this set of facts 
Copernicus derived his argument for the actual 
rotatory movement of the earth. 

Two Possible Explanations. This common pro- 
gression of all the objects that fill the sky may be real 
and actual and, if so, the theory of the earth's rotation 
is nullified. But it may be only apparent and illusory 
due to the circular motion of the earth. For if the 
earth be in rotation, it will by an unavoidable illusion 
cause the whole celestial sphere to seem to rotate in a 
contrary direction. Concede for the sake of argument 
that in each twenty-four hours the earth rotates on an 
axis from west to east, then the heavens will apparently 
be set revolving from east to west in the same period. 
Is it not true that every motion whatever begets a 
similar illusion? 

In a word, the diurnal movement of sun, moon, and 
stars in a common direction from east to west, is per- 
fectly met by either of two hypotheses, one that the 
movement is actual and inherent, the other that the 
celestial bodies, of themselves motionless, are set in 
apparent revolution by the actual rotation of the 
earth. 



30 Rotation of the Earth. 

The More Probable Theory. It remains to ask which 
of the two hypotheses is the more probable. To 
make up our minds, we have but to think of the 
diminutive size of the earth as compared with the 
hugeness of the entire celestial sphere. 

On the one hand, we have the earth, proportionally 
only a speck in space as even Ptolemy admitted, and 
on the other the entire universe of bodies, the earth 
alone excepted. Among these other bodies is the sun, 
which we have found to be gigantic compared with 
the earth. The celestial sphere contains, besides, the 
multitude of the stars. How far away are they? 
Evidently not near enough to the earth to fall towards 
its surface. How large are they? Large enough at 
least to have remained burning unconsumed through- 
out the length of human history. How numerous are 
they? The naked eye counts them by thousands, 
but the telescope numbers them by millions and tens 
of millions. 

Now is it within the range of probability that all 
these celestial bodies are physically subservient to the 
earth ? Can it be their appointed role to achieve each 
day a revolution round a body so insignificant in size? 
Shall tens of millions of bodies be made the satellites 
of one ? Shall the sun and other giant masses of the 
heavens attend upon the earth, a pygmy? 

Enormous Speeds Postulated . The argument against 
an actual diurnal movement of the entire heavens is 
already strong, but it appears constantly more cogent 
the more we give it thought. Think, for example, 
of the rate of speed which such an hypothesis attributes 
to the stars ! If the earth rotates, its equator speed of 
1,000 miles an hour is already enough to astound the 



Rotation of the Earth. 31 

average thinker. But if the heavens are in motion 
and not the earth, then the very nearest of the stars, 
were it only a mile away, must travel at still higher 
speed. And the speed required will increase mathe- 
matically with the distance from the earth's centre. 

Thus to the moon, the nearest of celestial objects, 
would be imputed a velocity sixty times 1,000 miles 
an hour, for sixty to one is the ratio of its orbit with 
the circumference of the earth. Project imagination 
into space to the distance of the sun, and figure if 
possible the size of its orbit and the consequent speed 
of its daily revolution. Go yet farther into space, out 
to the stars that lie on the boundaries of the universe, 
some of them so distant that no telescope has yet 
discovered them. The farther away, the more en- 
hanced the speed. Even with the vaguest knowledge 
of star distances, we soon come to the conclusion that 
if the heavens actually turn as they appear to do, we 
must ascribe to the stars a velocity that is all but 
inconceivable. 

Harmony of Movement. And all the celestial 
bodies, whatever their distances, are made to move 
as one. The more remote are brought into accord 
with the nearest. The stars preserve always the same 
alignment. More incredible even than the tremendous 
velocity that would be needed is the supposition that 
ten million bodies at unequal distances from us should 
go round and round at such harmonious rates as always 
to present the same groupings and the same unaltered 
formations. 

But make the simple supposition that the earth is 
rotating once each day and the unity and harmony 
of the celestial motions is at once explained. Assign 



32 Rotation of the Earth. 

but this single motion to the earth, and the common 
movement of the great celestial sphere must fol- 
low as an inevitable necessity. Deny it, and there 
is postulated for those other worlds, the sun and 
stars, a movement so terrific and yet so well-ordered 
that it is absolutely unimaginable. The number of 
stars now known to us is in the neighborhood of fifty 
millions. The chances in favor of the earth's rotation, 
then, are as fifty millions to one. 

The Argument Summarized. This is the principal 
argument in favor of rotation. Stated briefly, it 
tells us that it is far more probable that our earth is in 
rotation than the immense unmeasured heavens with 
all the bodies they contain. It was the argument of 
Copernicus, the illustrious priest-astronomer of the 
sixteenth century, and presented by him to the world, 
it effected a revolution in human thought. For four- 
teen hundred years men had accepted the doctrine 
of appearances, believing with Ptolemy that the 
earth is stationary and the skies are in motion. 
Copernicus, by establishing and proving the rotary 
movement of the earth, started a new epoch in the 
science of astronomy. 

Additional Proofs. To the argument of the priest- 
scientist we are able now to add two others, thanks to 
the use of modern instruments. The first is an argu- 
ment of analog}^ vouchsafed us by the revelations of 
the telescope. The telescope shows us conclusively 
that certain bodies in space are in rotation. There 
is positive evidence of this for the sun, the moon, 
and the planets Mars, Jupiter, and Saturn. The 
evidence is so precise that in each case we can measure 
the rotation-time. 



Rotation of the Earth. 33 

The rotation of a sphere is, then, not an unknown 
thing in nature ; it is very probably nature's common 
law. For could we examine the other heavenly bodies 
favorably, we should probably observe in them the 
same phenomenon. The only celestial bodies favor- 
ably placed for observation are seen to revolve on an 
axis. By analogy we esteem it highly probable that 
the earth, a globe like these, is endowed with a move- 
ment of rotation. 

Pendulum Experiment. The second new argument 
is based on the famous pendulum experiment, first 
performed by Foucault at Paris in 1851, often re- 
peated since and always with the same results. The 
experiment consists in hanging a very long pendulum 
from the roof of a high building and setting it swinging. 
As it swings, it is made to trace its course in a bed of 
sand spread beneath. By nature's law the pendulum 
continues to oscillate in an unaltered vertical plane. 
But the sand bed which it grazes is found to turn with 
the rotation of the earth. As the hours slip on, the 
pendulum is seen to trace in the sand not one single 
line, but a series of intersecting lines like the several 
diameters of a circle. 

Only a displacement of the earth from its first 
direction can explain this resulting pattern of inter- 
secting lines. The pendulum experiment supplies 
an argument we could scarcely have hoped for, an 
observational proof of the fact which Copernicus had 
alleged. 

Epitome of Reasoning. Such is the trend of the 
argument, first, the fact that motion never reveals 
itself directly and that in its regard we are often the 
victims of illusion; secondly, the marked disparity 



34 Rotation of the Earth. 

of size between the earth and the heavens; thirdly, 
the analogy of other bodies in space; and, finally, the 
observational proof from the movement of the pendu- 
lum. If we take reason and not appearance as our 
guide, we shall not hesitate. There are few facts in 
nature for which we have a richer cumulus of testi- 
mony than the rotation of the earth. 



CHAPTER IV. 
EARTH'S REVOLUTION AROUND THE SUN. 

The sun shares, of course, in the apparent daily- 
revolution of the celestial sphere. Like all other 
bodies of the firmament, it rises, culminates, and 
sets, once in each day. But it apparently has in 
addition a proper motion of its own. It is not al- 
ways attached to the same group of stars, but jour- 
neys slowly through the constellations, in a very 
definite orbit, however, and with uniform speed. 
Effort should be made to understand well this par- 
ticular movement of the sun, for from it we infer 
the most important truth in the whole science of 
astronomy, the fact of the earth's annual revolution. 

Some Motions Easily Visible. Strange to say, 
among all ordinary celestial motions the special one 
of which we now speak is the most difficult of dis- 
cernment. That the moon is changing its position 
among the stars, can be learned without any difficulty 
by simply watching its course from night to night. 
From one evening to the next, it will be seen to have 
shifted its position towards the east by the consider- 
able distance of thirteen degrees, a space equal to 
twenty-six times its own diameter. 

The movement of the planets also is, if not easy, 
at least not difficult to discern. For when they shine, 

35 



36 Revolution of the Earth. 

they are accompanied by certain groups of fixed stars 
in whose midst they are placed. And watching the 
planets for a certain period, we shall see them slowly 
or quickly dislodging themselves from their first 
positions and entering new groups of stars. It re- 
quires but little careful watching to convince ourselves 
that Mercury, Venus, Mars, Jupiter and Saturn are 
wandering or planetary bodies. And they have been 
known as such from time immemorial. 

Discernment of Sun's Movement. But with the sun 
the case is different. For when it shines, the back- 
ground disappears, the stars flee apace or fade into 
obscurity, and we have left no visible guide-posts by 
which to plot its course. But it is advancing on the 
stars none the less, in the same direction as moon and 
planets, namely to wards the east, and in approximately 
the same path. And could the sun be eclipsed once 
each day, thus permitting us to view the particular 
stars by which it is environed, then we should have 
ocular evidence of the sun's independent movement. 
We should then behold the solar orb moving steadily 
forward in its allotted path at about the rate of one 
degree a day, twice its apparent breadth, and complet- 
ing the circuit of the heavens in exactly one year.* 



* An easy way of proving to one's own satisfaction that 
the sun is thus moving is to notice the stars on the meridian 
at midnight. At that moment the sun is on the opposite 
meridian. Now the meridian stars at midnight are never 
quite the same from night to night. Every star advances 
towards the west night by night at the approximate rate of 
one degree. A little reflection will show that this is due to 
an independent motion of the sun towards the east amounting 
to about one degree a day. 



Revolution of the Earth. 37 

In view of the difficulty of detecting the sun's 
change of position among the stars, it is remarkable 
that it was discovered so early in the history of our 
race. What man first discerned it and in what epoch 
we do not know, for the discovery belongs to pre- 
historic times. But however and by whomever 
made, the discovery of the sun's independent motion 
marked, as Newcomb justly says, the birth of the 
science of astronomy. 

Knowledge of the Ancients. Indeed, the knowledge 
of early peoples concerning the sun's joumeyings was 
much more complete than has thus far been intimated. 
They knew accurately the groups of stars through which 
the sun pursued ever its unvarying way. These 
constellations, twelve in number and of all stellar 
groups the chief in interest, formed what came to be 
know as the Zodiac, and are the twelve whose symbols 
have been placed in the hallway of our Boston Public 
Library. 

Not alone its zone of movement had been deter- 
mined but its exact line as well, and on their astron- 
omical globes the ancients could draw a line repre- 
senting perfectly the orbit of the sun. This path 
they called the Ecliptic, for only on this line could 
eclipses occur. The two points where the ecliptic 
crossed the equator of the heavens they called the 
Equinoxes, the vernal and the autumnal, for when 
the sun reached either of these points, the night (in 
Latin nox) was equal to the day all over the globe. 

Day by day at regular pace the sun advanced 
along this orbit, always approximately one degree, 
until at the end of exactly one year it had completed 
the round of the heavens. It will help us much 



38 Revolution of the Earth. 

in our consideration of the sun's movement if we 
can realize as keenly as did the ancients that back 
of and around the sun there alwa5^s lies a certain 
group of stars, some one determined sign of the 
Zodiac, which would shine forth and appear of a 
definite figure were it not for the sun's superior 
light. 

Inference of the Ancients. That the sun's move- 
ment thus described was actual and inherent, the 
ancients never for a moment doubted. For them 
phenomena meant reality and their only doctrine was 
that of appearances. And the belief of the ancient 
world was crystallized in Ptolemy's great book of the 
second century, "The Almagest," in which it was 
taught that our earth was the centre of the annual 
revolution of the sun, as it was also the centre of the 
diurnal movement of the entire celestial sphere. In 
the order of movement they gave supremacy to the 
earth, around which as parent body the sun must 
revolve. 

ARGUMENTS FOR REVOLUTION. 

Theory of Copernicus. It was reserved for Coper- 
nicus, priest of the fifteenth and sixteenth centuries, 
to undermine this belief of the ancient and medieval 
world, by asserting the merely apparent character of 
the sun's movement among the stars. He showed 
conclusively that all the phenomena could be ade- 
quately explained by the mere supposition that our 
earth is the revolving body, moving forward in space 
in a large circular orbit whose centre is the sun. Thus 
he wrested from the earth the place of honor, trans- 
ferring it to the sun. 



Revolution of the Earth. 39 

Not lightly or without question should we admit 
a supposition so strange. Again there comes to our 
minds the thought that if the earth is thus altering 
its position in space and at a rapid rate, some sensible 
impression should arise to make us conscious of it; 
all the more that we are now assigning a second 
motion to the earth, a forward march through space 
superadded to the movement of rotation previously 
established. Though one holds true, the other does 
not follow, and we must examine its claims as ques- 
tioningly as if it stood alone. Appearances witness 
to a stationary earth, and establish in us a prepos- 
session which only the most cogent of arguments 
shall be able to eradicate. 

His Arguments. The argument of Copernicus 
favorable to the revolution of the earth was drawn 
from the apparent motion which actual motion never 
fails to produce. No body whatever can be set in 
motion without begetting in neighboring objects the 
apparent effect of movement in a contrary direction. 
To our sense of sight the illusion is complete; only 
by reasoning can we get rid of the false impression 
and distinguish correctly between the genuine mo- 
tion and its counterfeit. 

Analogy of a Vessel. Imagine, for example, a 
vessel patrolling a harbor at night surrounded on all 
sides by the harbor lights and the beacons gleaming 
from the shore. As the boat progresses, every sepa- 
rate light within range of view seems veritably endowed 
with onward motion. Let us suppose that the 
vessel in which we are interested describes a wide 
circle around some island on which is mounted a 
powerful beacon light. Let this particular lighthouse 
be the centre of our study. 



40 Revolution of the Earth. 

As the ship advances, the Hghthouse assumes con- 
tinually new positions on the horizon. Now it is set 
against Winthrop to the north ; describing a quarter 
circle, it is seen to the west projected against Boston 
as a background. Now it has moved to the south 
and has found in Quincy or Weymouth its tempo- 
rary setting, and now it is backed by the promonto- 
ries to the east, those of Hull and Allerton. Finally, 
when the vessel has completed one lap of its journey, 
the beacon light is again in its original position, 
projected against the highlands of Point Winthrop. 
Meantime the actual motion of the ship has been so 
quiet and regular that the passengers aboard thought 
themselves at rest and of necessity transferred to the 
beacon light the motion that was their own. 

Application of the Analogy. If now the analogy be 
applied, the beacon light becomes the sun, the moving 
vessel is our earth, and for the background of the 
harbor-shores is substituted the belt of constellations 
that we call the Zodiac. The sun's projection on the 
Zodiac at any moment will depend on the position 
of the earth. As the earth moves, so must the sun 
appear to move in an orbit that parallels the earth's 
actual orbit in every particular. In direction and in 
rate of speed the sun's revolution will be a perfect 
replica of the earth's. 

The earth's passengers, moreover, all the while will 
of necessity be unaware of their own forward progress, 
and if questioned will answer unhesitatingly that the 
motion belongs to that brilliant beacon set in the 
heavens. The analogy holds perfectly and there is 
no room for doubt that, given a circular motion of the 
earth, all the phenomena of the sun's apparent move- 
ment would be perfectly explained. 



Revolution of the Earth. 41 

Value of Copernicus' Argument. Such was Coper- 
nicus' reasoning in favor of the second motion which 
he accredited to the earth. As it stood, it was but a 
probable argument and could not generate certainty. 
It founded a theory, it did not establish a truth. To 
beget certainty it needed the reinforcement of other 
arguments, which happily were not long delayed. 

It was in 1543 that from his death bed, Copernicus 
published the book containing the enunciation of his 
two propositions, that the earth rotates on its axis and 
revolves about the sun. As a loyal child of the Church 
he dedicated his work to the then reigning Pontiff, 
Pope Paul III. 

LATER PROOFS. 

Argument from the Planets. Within little more than 
fifty years from that date, a host of new facts had 
been discovered by a trio of eminent astronomers, 
Tycho Brahe, Kepler, and Galileo, on which was to 
be based another and better argument for the earth's 
revolution. These facts bore on the group of planets 
called Mercury, Venus, Mars, Jupiter and Saturn. 
An integral part of the Ptolemaic theory had been that 
these planets revolved about the earth as did the sun 
and moon. For this reason Ptolemy's system was 
called the geocentric or earth-centric, because it 
made the earth the centre of all celestial motions, 
ordinary and extraordinary. 

What a blow it was to this entire doctrine when it 
was learned beyond all fear of error that the five 
planets in question are revolving about the sun and 
not about the earth! More accurately than his 
predecessors, Tycho Brahe measured the orbits of 
these five important luminaries; Kepler reduced the 



42 Revolution of the Earth. 

calculations and combined them into a system; and 
finally Galileo showed with his telescope the phases 
of Venus, an irrefragable proof that this planet at 
least was coursing about the sun. 

Copernicus Confirmed. When the three scientists 
mentioned laid down their pens, there was no further 
room to doubt that the sun was the focal centre of the 
orbits of the five planets from Mercury to Saturn. 
Could it still be true that the sun with its five at- 
tendant globes was but a satellite of our earth ? Was 
it not more likely that the earth was a planet also? 

The sun was proved to be a centre of five motions. 
Why not probably of a sixth as well? The sixth 
body, the earth, lay right in the midst of the group 
of five, two of them, Mercury and Venus, being 
plainly nearer the sun than was the earth, and the re- 
maining three farther away. The entire arrangement 
could suggest only the conclusion that the earth is 
truly a planet, as much so as Venus or Mars, and that 
around the sun as a focal centre the earth pursues its 
annual journey. Thus was Copernicus' theory cor- 
roborated by the findings of his successors. 

Sir Isaac Newton. Just a hundred years after 
Copernicus and within a year of Galileo's death, there 
was bom another genius, Sir Isaac Newton, who, 
before his life was ended, would give to the world 
his law of universal gravitation. By this law he was 
to set the crown on the labors of his predecessors. 
The mathematical work had been completed, so well 
and accurately indeed that Kepler could draw on a 
chart a series of closed curved lines representing 
faithfully the paths of all the planets. For Newton 
it was reserved to discover the force in nature that 



Revolution of the Earth. 43 

obliges the planets to follow just such orbits in 
preference to all others. This force was universal 
gravitation. 

Effects of Gravitation. If the moon revolves about 
the earth instead of following, as it naturally would, a 
straight undeviating path, it is in virtue of the earth's 
greater mass and superior attraction. If Venus or 
Mars circles about the sun instead of pursuing a 
rectiHnear course as the first law of motion would 
demand, there must be as for every circular motion 
some central force holding the planet in check, and 
this central force is the sun's superior attraction. 

In the dynamic order, the lesser body always waits 
upon the greater and, unless too distant, is drawn 
by it away from its original direct path into a curv- 
ilinear orbit at whose focal centre is the greater body. 
Gravitation, in a word, makes the planetary orbits 
to be what they are, permitting no exception. 

Application to the Earth. And now it is timely to 
recall the results of an earlier chapter of this volume in 
which it was shown that the sun is a globe over a 
million times as voluminous as the earth. In the 
amount of matter contained, the ratio is indeed some- 
what less, but it still leaves the sun preponderant 
over the earth by three hundred thousand to one. 

According to nature's law, then, and in keeping with 
all analogies, the earth must revolve about the sun. 
The sun's superiority demands it, not merely as a 
congruity, not merely as something fit and becoming, 
but as a necessary consequence of nature's inexorable 
law. The law of gravitation holds everywhere else, 
determining the courses of the planets and of their 
smallest satellites. It must apply also to the earth, 



44 Revolution of the Earth. 

and obedient to it the earth shall pursue in regular con- 
trolled orbit a yearly revolution around its dominant 
body, the sun. 

Still another proof of this cardinal scientific truth 
is found in text-books of astronomy, derived from the 
phenomenon known as the Aberration of Light. But 
it is quite too difficult to be unfolded in a popular 
presentation such as this is meant to be. Suffice it to 
say, that the new proof confirms by an appeal to fact 
all the considerations here brought forward. 

Summary of the Reasoning. Our effort in this 
chapter has been to summarize the triple argument 
in favor of the earth's forward movement in space. 
Contrary to our sensations this motion seems, but 
what mere argument of sense will stand before such 
a cumulus of testimony? Reviewing the evidence, 
we find that there are three separate lines of derQon- 
stration: the argument from the ease with which 
our senses are deceived in the matter of real and ap- 
parent motions; the argument of analogy drawn 
from the observed revolutions of the planets ; and the 
proof from relative size and consequent attraction 
under the law of universal gravitation. 

From a daring speculation the theory of Copernicus 
has grown into an established truth. If the first 
observation of the sun's independent motion marked 
the birth of the science of astronomy, his correct 
explanation of the sun's independent motion marked 
no less truly the rebirth of the science. His enuncia- 
tion of the earth's revolution was a triumph of astron- 
omy, opened a new era in the study of the heavens, 
and b}^ solving one part at least of the puzzle of the 
firmament proved its author a prophet and a seer. 



CHAPTER V. 

NICHOLAS COPERNICUS. 

From many points of view the career of Nicholas 
Copernicus is worthy of recital. He is quoted in 
nearly all text-books and manuals of astronomy and 
always, where comment is added, in terms of highest 
praise. Authorities as competent in their field as 
Newcomb, Ball, and Miss Agnes Gierke, to mention 
but a few of many, do not hesitate to bestow the 
title great on the man himself and on the system 
which he elaborated. And despite later revisions, the 
modern system of astronomy continues to bear his 
name. 

He belonged to a period of history remarkable for 
its many-sided accomplishments, and, as it appeared at 
the time, critical for the life of the Church. He lived 
in the full flower of the Renaissance, and was the 
contemporary of Columbus and Luther. Columbus 
gave to the world a new hemisphere, Luther gave to 
the world far less happily a new religion, fortunately 
failing in his attempt to dispossess the old, and 
Copernicus simultaneously gave to the world, as a 
contemporary bishop expressed it, a new heaven 
and a new earth. 

Sources of Information. To trace briefly the life 
of such a man is quite pertinent to our purposes, and 

45 



46 Copernicus. 

may be regarded as opportune, now that his astronom- 
ical system and its proofs have been sufficiently 
described. 

Obscurities of detail are to be expected in seeking 
to learn completely the life-history of a man of his 
modesty and self-effacement, living moreover in an 
era when biography was cultivated less than now. 
There are missing important data needed for the 
complete exposition of his life. But the main out- 
lines are clear, and earlier errors have been corrected 
and interstices supplied, thanks to special studies of 
the past decade. In two excellent recent volumes 
from Catholic authors, Walsh's Churchmen in Sci- 
ence and Volume IV of the Catholic Encyclopedia, 
may be found good summaries of what is now well 
ascertained of the life of this important figure in the 
history of science. 

His Family and Country. Copernicus' life covered a 
period of seventy years, spanning the fifteenth and six- 
teenth centuries. He was born in 1473 in Thorn, now 
of eastern Germany, and died in 1543 at Frauenburg 
on the Baltic coast, also at present a town of eastern 
Germany. He was more likely, however, of Polish 
ancestry and blood than German, at least on his 
father's side. 

The family were not merely loyal but devout 
Catholics, giving three of four children to the direct 
service of the Church. Moreover, his maternal uncle 
was a bishop, and to the guidance and resources of 
this prelate, Nicholas owed the remarkably extensive 
education which he received. 

Extent of His Education. His entire schooling 
from the age of ten, when he lost his father by death, 



Copernicus. 47 

was directed by his uncle, and it was not completed 
till he had passed his thirtieth year. He made his 
college course at Cracow in Poland, repairing thither 
when eighteen years of age. At twenty-four he left 
Cracow for Bologna in Italy to pursue studies of 
university rank. Here he met the astronomical 
teacher, No vara, who though himself a follower of 
Ptolemy, first suggested to the youth's mind that the 
correctness of Ptolemy's system might fairly be 
investigated. 

In the year 1500 he was at Rome attending the 
Jubilee celebration, and incidentally delivering some 
lectures on his favorite science. From 1501 to 1503 
or even later, he added to his store of knowledge by 
following courses in medicine and jurisprudence at 
Padua and Ferrara, taking the degree of doctorate in 
Canon Law at the university of the latter city. 
When he returned to his natal country in 1505 or 
thereabouts, he was unquestionably supplied with a 
rich mental equipment. Few^ there are today that 
might not envy his educational opportunities. And 
these were allowed him, be it remembered, at a time 
when all education in Christian Europe was under the 
auspices of the Catholic Church and most of it under 
her direct control. 

His Mature Achievements. The versatility of his 
mature accomplishments was proportional with the 
breadth and A^ariety of his education. Remembered 
chiefly as an astronomer, he was in no sense a narrow^ 
speciaHst but a man of broad culture and manifold 
occupation. Devoted ecclesiastic, student and teacher 
of the sciences, practitioner in medicine, and financial 
counsellor to the State, he was each and all of these, 



48 Copernicus. 

and in each pursuit won distinction and applause. 
Incidentally he was by turns, though on a smaller 
scale, an artist-painter, a writer of verses on sacred 
themes, and a translator of Greek authors. 

VOCATION AND AVOCATIONS. 

His Profession. By vocation and profession he was 
an ecclesiastic. Appointed a canon of the Cathedral 
of Frauenburg at the age of twenty-five through the 
influence of his uncle, he retained the post until his 
death. For many years his studies in Italy and later 
his attendance on his uncle-bishop at Heilsberg, kept 
him from actually fulfilling the duties of the canonry. 
But from 1512 on, with the exception of one interrup- 
tion of four years, and therefore during all but four 
of the last thirty-one years of his life, he appears to 
have served actively and abidingly as a member of 
the Cathedral chapter. 

Was he an ordained priest? Unfortunately we 
cannot answer this question beyond all cavil, for there 
is no record of his ordination extant. No more, how- 
ever, does there remain any record of his medical 
degree and yet we know he practised extensively the 
art of healing. Many converging facts insinuate 
that he had entered the priestly order, and the care- 
ful biographer of the Catholic Encyclopedia deems 
it probable that he had received the sacred priesthood. 

His Offices in the Church. His very office of canon 
would seem to intimate this. Further, in 1512 he 
participated in the election of the new bishop of 
Frauenburg. From 1516 to 1520 he was admin- 
istrator of the diocesan castle of Fallenstein. At the 



Copernicus. 49 

death of Frauenburg's bishop in 1523, he was made 
administrator of the diocese. In 1537, he was named 
by the King of Poland as one of four candidates for a 
vacant episcopal see. His remains lie interred in the 
crypt of the Cathedral where he officiated so long as 
canon. 

These numerous facts accumulated make it quite 
probable that he was of priestly rank. Writers, 
however, who court scientific accuracy of statement 
will give to him as certain the titles of ecclesiastic, 
churchman, and officer of the church, adding, if they 
have occasion to do so, that he was in all likelihood 
an ordained priest. And whatever his precise dignity, 
of his fervor and fidelity in the discharge of his eccle- 
siastical duties, there is not the slighest reason for 
doubt or even for cavil. 

Relatively Minor Occupations. Without prejudice 
to his ecclesiastical profession, he practised also the 
art of medicine. By all who obtained his services 
in this field, he was rated a skilful physican. It is 
to be carefully noted, however, that medicine was 
was not his profession. He practised only privately, 
never professionally. Rather strange it is to learn 
that he exercised his medical skill in favor of two 
classes, the noble or very rich and the very poor. 
Family friendship was the motive in the one case and 
charity in the other. That he ministered to the poor 
always without charge, reveals one of the many 
admirable elements of his character. 

Whatever else we might look for in Copernicus' 
life, we should scarcely have expected to find an 
excursion into the field of public finance. But this 
subject, too, engaged his interest, and beginning in 



50 Copernicus. 

1522 he wrote a series of financial treatises. They were 
so excellent that they received instant notice from 
the ruler of Germany, who thereupon claimed his 
services as a deputy counsellor of finance. Again 
without smallest detriment to his true vocation or 
his numerous avocations, Copernicus discharged 
acceptably the duties of this additional office during 
a period of seven or eight years. 

ASTRONOMICAL CAREER. 

His Interest in Astronomy. Our hero is best known 
to the world, however, as an astronomer, and in this 
capacity will be longest remembered. All who know 
anything of Copernicus are aware that he proposed 
a new theory of the heavens which was destined to 
effect a revolution in the teaching of the science. It 
is in this special r61e, then, that we have now to con- 
sider him, inquiring first how large a share astronomy 
played in Copernicus' life. 

If we take life to mean the period of one's mature 
manhood, then we may say truly that Copernicus' 
interest in astronomy was lifelong. From his student 
days until his death, he was not merely interested in 
the science but devoted to it. The pursuit of this 
learning was with him something more than an avoca- 
tion or diversion, it was as it were a second vocation, 
and might have been called a passion in one less self- 
controlled. 

From Novara, his professor at Bologna, came his 
first impulse in this direction. His own lectures at 
Rome in 1500 further strengthened the impulse, 
determining him to make the astral science his 



Copernicus. 51 

specialty. And thereafter for a period of more than 
forty years his astrononiical researches went hand in 
hand with the performance of his ecclesiastical 
functions. 

Reform of the Calendar. Already in 1514 his 
reputation as an astronomer was considerable enough 
to have won the notice of the then reigning Pontiff. 
Leo X thus early had thought of reforming the Julian 
Calendar which was now proving defective, and 
appealed among others to Copernicus to assist in the 
work of reconstruction. The latter, after giving due 
attention to the project, answered that the time was 
not yet ripe for reforming the calendar properly. 

The request from the Pope spurred him on, however, 
to an increased ardor for these studies, and impelled 
him to gather statistics and make computations which 
were later used when the Calendar was actually revised 
under Gregory XIII. Thus from Italy and Rome came 
the second inspiration to make astronomy his lifework. 

Preparation for his Magnum Opus. No man of his 
period was better qualified to undertake the task of 
reconstructing radically the system of astronomy then 
in vogue. He was a thorough mathematician, 
according to one authority the best of his time. He 
was well versed in Greek, and thus had access to the 
writings of the ancient masters in their original text. 
Moreover, wherever he dwelt, he continued to pros- 
ecute his studies assiduously, and the towers of 
Heilsberg, Aliens tein, and Frauenburg, availed him 
as observatories from which to trace and measure the 
courses of the heavenly bodies. 

In announcing his final results he himself testified 
that they are the fruit of long and laborious observa- 



52 Copernicus. 

tion. And his epoch-making book gives ample 
evidence that his observation of the heavens had been 
untiring. 

His Work "in Petto." By the year 1531, when he 
was now fifty-eight years of age, he had finished his 
great work, "On the Revolutions of the Heavenly 
Bodies." The printing of the book, however, was 
delayed until just before his death, which occurred 
some twelve years later. But from this delay it would 
be a mistake to infer that he or his chosen theories were 
without influence on the astronomical thought of his 
time. 

Although he refrained for well-considered reasons 
from publishing his new doctrine to the world, he did 
not abstain from teaching it privately. To a few 
favored disciples he made known his theory, dis- 
tributed among them an abstract of his larger work, 
and through their instrumentality caused the new 
doctrine gradually to spread. In 1533, a certain 
scholar made thus acquainted with his views, lectured 
before Pope Clement VII on the Copernican solar 
system (note the significance of the title), and was 
rewarded for his effort with a gift of rare value. 

From 1536 on, Copernicus was repeatedly urged 
by his intimates to publish his work, among others 
by a cardinal and a bishop. At last yielding to their 
entreaties, he delivered his manuscript to the press in 
what proved to be the final year of his life. 

Reasons for Delay. Some have interpreted Coper- 
nicus' delay in publishing as a clear sign that he 
dreaded to expose his opinions to the church author- 
ities, fearing ecclesiastical censure if not actual 
persecution. Andrew D. White, adopting here as 



Copernicus. 53 

always an extreme view, enumerates Copernicus 
among the scientists who became victims of persecu- 
tion at the hands of theologians. But as far as 
Catholic theologians are concerned, all the facts argue 
to the contrary. By Luther and Melancthon during 
his life, and by their followers after his death he was 
indeed opposed, and his theories were condemned 
as running counter to the Scriptures. But from his 
co-religionists, including men of high position in the 
Church, he received, as has been indicated above, 
the most ample encouragement and support. 

Not fear of persecution but distaste for controversy 
was his sole motive for delay. He was quite aware 
that his scientific system was novel and revolutionary. 
He knew, too, that it might be mistakenly construed 
as at variance with Scriptural teachings. For fear, 
therefore, of becoming embroiled in controversies 
which to his retiring nature would have been most 
unwelcome, he put off indefinitely the publication to 
the world of his great discovery. Thus is shattered 
the charge that Copernicus feared persecution from 
the Church authorities. The best proof of his con- 
fidence and loyalty is that before publishing he added 
a Preface dedicating his volume to the Holy Father. 
The dedication was accepted. And the very first 
parts issued are now in the Vatican library. 

Reception of the Work. The story of the manner 
in which the world received his masterpiece, brings 
us perforce to the period following his death. It is 
quite consonant with the history just given. From 
the start the book was antagonized by some non- 
Catholic theologians, as he himself had anticipated. 
But it was absolutely unopposed, as far as we know, 



54 Copernicus. 

by any Catholic for over seventy years. Then arose 
the unfortunate GaHleo controversy, in which Coper- 
nicus' work was inevitably involved. 

As an incident of the Galileo case, the book of the 
master was conditionally condemned by the Congrega- 
tion of the Index. The Congregation required that 
eight sentences of Copernicus' text should be altered 
so as to read that the system there expounded was 
merely an hypothesis and not yet an established truth. 
Thus altered, the volume might be read with perfect 
freedom. Finally, when the time came that the truth 
was considered to have been definitely established, 
the condemnatory decree was removed from the In- 
dex, this being in 1758 under Benedict XIV, and 
thereafter the work in all its parts enjoyed complete 
immunity. 

Death of Copernicus. The last narration has 
brought us far beyond the actual boundaries of Cor- 
pemicus' life. The flame of his genius had been with- 
drawn from the world in 1543. Thanks to his own 
caution, his life had gone on to its close like a tranquil 
river, unruffled by the storms which reactionary hos- 
tility was seeking to arouse. It is a pathetic incident 
in the career of this venerable man that the first 
printed copy of his book was brought to him only on 
his dying day. He was then too weak to read or 
even see the valued tome, but it was reverently made 
to touch the dying hands of its author before he should 
be taken by his Maker to a literally "new heaven and 
new earth." 

His Monuments. On his tomb, says his biographer, 
is inscribed the epitaph he himself had chosen, "I ask 
not the grace accorded to Paul nor that given to Peter ; 



Copernicus. 55 

give me only the favor Thou didst show the thief on 
the cross." Monuments to his memory have since 
been erected at Thorn where he was born, and at 
Cracow where he studied. But the most precious of 
all his material memorials is the monument that sur- 
mounts his tomb in his own loved cathedral of Frauen- 
burg. 

In the words of Dr. Stoughton, a Protestant divine, 
there is there "painted a half-length portrait, pale, 
thin, aged, but with an expression of countenance in- 
telligent and pleasant. His hair and eyes are black; 
he is habited as a priest ; his hands are joined in prayer. 
Before him is a crucifix, at his feet a skull, and behind 
him are a globe and a pair of compasses. His devo- 
tion, his deadness to the world, and his love of science 
are thus aptly symbolized." 



CHAPTER VI. 
THE PLANETARY SYSTEM. 

The chief result of the triumph of Copernicanism 
was to estabhsh the earth among the planets as one of 
their order and number. This planetary system can 
now be made the object of special further study. 

The beginner in astronomy experiences a just pride 
when he first learns to locate and identify the planets 
as distinguished from the fixed stars, and in his use of 
the telescope he will have no more pleasing experience 
than his detection through this instrument of such 
picturesque planetary phenomena as the phases of 
Venus, the moons of Jupiter, and the rings of 
Saturn. 

Planets and Stars Compared. A merely superficial 
observation of the sky at night would discover no 
distinction between the planets and the stars. To 
the careless observer both would appear indifferently 
as shining points and would be classed by him under 
a common designation. But closer study discloses 
three distinguishing factors, of which two at least are 
available as criteria for identifying the planets. 

The planets are wandering bodies, moving from 
place to place among the constellations, whereas the 
stars are stationary or apparently so, maintaining 
from age to age the same alignment. Further, the 

56 



The Planets. 57 

planets are of themselves dark bodies like the earth, 
appearing bright only because they reflect and mirror 
the light of the sun ; whereas the stars are intrinsically 
bright objects like the sun or any terrestrial source of 
flame or fire, appearing lightsome therefore because 
of their own native luminosity. 

The distinction just indicated is the only essential 
difference between stars and planets. There remains, 
however, a third difference relatively to us, namely, 
that in the telescope the planets widen out into sen- 
sible disks that look like miniature moons, whereas 
the stars on account of their extreme distance never 
enlarge beyond mere points of light, no matter how 
powerful the instrument employed. 

The third test is one that can readily be applied by 
the possessor of a small telescope to such objects as 
Venus, Mars, Jupiter, or Saturn on the one hand, and 
any fixed star as Sirius on the other. Without the 
telescope one is compelled to fall back on the first test, 
assuring oneself by observation pursued from night 
to night that this or that indicated planet, as Jupiter 
or Saturn, is actually changing its position among the 
stars. 

Arrangement of the Planets. It would be very 
difficult for the beginner, even after locating the 
planets properly, to determine the order in which 
they are arranged. How shall he proceed to learn 
their relations of position and movement? He must 
first dismiss from his mind the illusion that they are 
equidistant with the stars. The telescopic test if 
rightly apprehended will convince him of the great 
disparity of distance between these two classes of 
celestial objects. 



58 The Planets. 

The fact is that the planets are grouped together 
in one part of universal space, and rather closely 
grouped if comparison be made with the stars. The 
nearest star is ten thousand times farther from us 
than the remotest planet. The planets form a group 
apart centred in the sun. 

Within the part of space they occupy, they are 
moreover disposed according to a well-established 
order. Some are less distant from the sun than is the 
earth, as evidenced by the fact that they never come 
into opposition, that is, they never appear in a quar- 
ter of the heavens opposite the sun, as they would 
surely do if their orbits ran outside the earth's. The 
planets nearer the sun than we are Mercury and Venus. 
All the others from Mars to Neptune come sometimes 
into opposition, appearing in mid-sky at midnight, a 
proof of their superior distance. The distances thus 
meted out to the several planets are never changed 
except within narrow limits. The planets are to be 
conceived as describing curved orbits of unequal 
radius around a common centre. 

Common Plane of Movement. It is very important 
for the understanding of the planetary system to 
learn that all their orbits, wide or narrow, lie almost 
in one plane. One is never to search for a planet near 
the poles, nor indeed in any part of the heavens other 
than the Zodiac. The Zodiac has been previously 
described as the specific girdle of constellations 
through which the sun's course runs. In the exact 
middle of the Zodiac lies the ecliptic, marking the pre- 
cise line of the sun's apparent journey. On any as- 
tronomical globe will surely be found delineated the 
Zodiac, everywhere sixteen degrees wide, and through 



The Planets. 59 

its centre and parallel with its borders the line of the 
ecliptic representing the sun's apparent path. 

The successful search for any planet will always 
discover it within the boundaries of the Zodiac, and 
for the greater planets, never rnore than seven de- 
grees from, the ecliptic, usually much nearer. If the 
ecliptic, which is a great circle of the sky dividing it 
into two perfect hemispheres could be tipped over and 
made to coincide with the horizon, another "great 
circle," then the members of the planetary group 
whenever visible would be seen on the horizon or hug- 
ging it closely. We should then surely say that the 
planetary orbits lie approximately in one plane. So 
shall we also as surely conclude if we realize that the 
ecliptic is, astronomically speaking, as definite a circle 
or line as the horizon. 

It is approximately correct, therefore, to draw the 
orbits of all the planets on the same flat page, and it 
is near the truth as well as helpful to the imagination 
to picture these bodies as so many ships riding on a 
level ocean in circular orbits of unequal radius around 
some chosen central island. 

Common Direction of Movement. Moreover, all 
the planet-ships sail over the imaginary ocean of space 
in a similar direction, having the sun-centre always 
at their left. Observation of the planets spread over 
a few months will convince the interested student that 
their progress through the Zodiac is in a common 
direction from west to east. Proceeding it is true at 
unequal rates of speed, they yet march on from Aries 
to Taurus to Gemini, always towards the east. Or 
if at times by exception they appear to turn in their 
course, — for some reader has probably heard of " retro- 



60 The Planets. 

grade motion," — their retrogression can be perfectly 
explained as unreal and due to the simultaneous move- 
ment of our observatory the earth. 

The planets' direction of movement is described as 
counter-clockwise, for such it would be if viewed from 
the north pole of the heavens. And the adjective may 
be comprehensively applied so as to describe not only 
the revolution of planets about the sun but also their 
axial rotations. And with relatively unimportant 
exceptions it applies to the satellites of the planets as 
well, defining the direction of their revolution and 
rotation. Thus the eight major planets and their 
more than twenty satellites both revolve and rotate 
in perfect harmony. 

Harmony of the Planetary Movement. There thus 
prevails in the planetary system a remarkable com- 
munity of movement both in plane and direction, 
embodying such order and regularity as we commonly 
associate with an intelligent author. In contemplat- 
ing the order observed, it is to be remembered that we 
are dealing not with tiny lamps but with great globes, 
many of them comparable in magnitude to our earth 
and some of them far surpassing it. These giant 
spheres are placed at very wide intervals, albeit the 
intervening spaces exhibit almost perfect proportion. 
There is no intrinsic reason why these massive orbs 
so unequally placed should agree so perfectly in the 
line and direction of their march. Apart from a 
governing law and a ruling intelligence it seems impos- 
sible to explain the orderliness of their movement. 

The Argument of Design. Long ago philosophers 
found in the starry heavens a satisfying proof of the 
existence of an all-ruling and supremely intelligent 



Jupiter. 61 

God. Their premise was the beauty of the sky and 
the order Hn ess of its movements ; their conclusion was 
the Deity. The argument was thus eloquently 
phrased by Minucius Felix, a Latin Father of the third 
century: "What can possibly be so manifest, so con- 
fessed, and so evident, when you lift up your eyes to 
heaven, and look into the things which are below and 
around, as that there is some Deity of most excellent 
intelligence by whom all nature is inspired, is moved, 
is nourished, is governed? . . . If on entering any 
house you should behold everything refined, well- 
arranged and adorned, surely you would believe that 
a master presided over it, and that he was much bet- 
ter than all these excellent things. So in this house 
of the world, when you look upon the heavens and 
the earth, its providence, its ordering, its law, believe 
that there is a Lord and Parent of the universe far 
more glorious than the stars themselves and the parts 
of the whole world." 

What modern astronomy has taught us of the won- 
derful order prevailing in the planetary system, must 
be adjudged a powerful reinforcement of Minucius 
Felix's excellent argument for the existence of a 
Supreme Deity. 

THE PLANET JUPITER. 

Just now (Feb., 1909) the planet Jupiter is visible 
evenings in the eastern heavens, rising a little before 
eight on the first of the month and a half -hour earlier 
in each successive week.* When at its best, as it will 

* One month later for each succeeding year. 



62 Jupiter. 

be in the period just ahead, it is many times more 
lustrous than any of the stars. Even among such 
companion lights as Sirius, Procyon, Regulus and the 
like, all of them first magnitude stars, Jupiter is un- 
mistakable by reason of its surpassing brightness. 

Here is a planet, then, that the veriest tyro in as- 
tronomy can now search for with absolute confidence 
of success. And when he comes upon it, let him set 
it down mentally, not as a star that shines by its own 
effulgence, but as a planet borrowing all its light from 
the sun ; not as a distant stellar world trillions of miles 
away, but as a near neighbor astronomically reckoned, 
one of a group that includes our earth; not as an 
independent primary body like the stars, the centre 
of whose orbits no one knows, but as a planet tributary 
and subordinate to the sun, on which it attends and 
round which it courses. 

The Jovian System. In the telescope and even in 
a good opera -glass, Jupiter presents one of the finest 
and most instructive of celestial spectacles. Its 
round disk will appear larger and larger according to 
the increasing power of the instrument employed, and 
in a good three-inch telescope will be seen crossed by 
two parallel cross-bands midway between which lies 
the planet's equator. 

Moreover, there will be found attendant on the 
planet four moons or satellites. They bear the same 
relation to Jupiter that our moon does to the earth. 
Their setting is not only esthetically interesting as 
being a fine morceau of the Creator's handiwork, 
but scientifically instructive as being a picture in 
miniature of what we believe to be the grouping of the 
entire solar system. 



Jupiter. 63 

The fact that these four gleaming lights, for such 
they appear, are always found with Jupiter whereso- 
ever it wends its way, is a proof that they are not fixed 
stars but, like their principal, planetary or wandering 
bodies. To them, indeed, as to our moon the name 
of secondary planet can be and is applied, their master 
or principal then being called a primary planet. But 
moon or satellite is a more distinct term for designat- 
ing a member of this class of celestial objects. 

Arrangement of the Satellites. It will be observed 
at once that the four moons of Jupiter are not disposed 
irregularly about the planet, above, below, or on any 
side whatsoever, but uniformly and systematically 
along one line. And by reference to the dark bands 
it can be made out that this line is an extension into 
space of the planet's equator. No matter when the 
planet be viewed, the satellites if visible at all will 
be found stretched along a single imaginary line. 

According to our simile of ships at sea, they must 
therefore lie in a common plane. Little gunboats 
cruising or deploying about their master battleship, 
they do not ascend above the warship's height nor are 
they depressed below it, but remain true to the ocean 
level. Their orderly maintenance of position is a 
reminder of what was postulated for the setting of the 
primary planets. Indeed, the sea in which they sail 
is merel}^ a portion of the great ocean plane that forms 
the scene of the larger evolutions of the planet fleet. 
Expressed technically, the plane in which Jupiter's 
satellites are located is identical with the plane of the 
ecliptic. 

Their Regularity of Movement. Finally, within 
this plane their career is not one of sodden rest but 



64 Jupiter. 

one of vivid motion. And here there is no reference 
to the forward advance through the star-groups which 
they share with their principal and for which the 
latter is responsible. But apart from this common 
motion, within their own system they assume new 
collocations and effect new groupings. Now grouped 
on the same side of the planet, now arranged in pairs 
at either side, at another time they seem more un- 
symmetrically distributed, one satellite striving to 
balance three. 

Nor must the amateur astronomer be disappointed 
if one or two members of the group play hide-and- 
seek at times behind the planet, for this they must do 
to pass from one side to the other. Mere casual 
observation thus discovers that Jupiter's satellites 
are in constant movement. It needs closer study 
to discern that their movement is orderly and sys- 
tematic and governed by a common law, that all these 
bodies are tributary to the planet, describing round it 
curved orbits of similar geometrical form and in the 
direction which we have designated counter-clock- 
wise. 

Interest of Their Discovery. Jupiter and his satel- 
lites evidently form a perfect system, its members 
regularly composed and its movements harmoniously 
ordained. When discovered by Galileo in 1610, 
the Jovian system was a revelation to the astronomical 
world. Here in space was plainly an example of a 
twofold motion, involved and yet not confused. The 
cycle of the planet about the sun and the epicycles 
of the satellites about the planet were blended into 
harmony. The orbits of the satellites were carried 
forward in the larger orbit of the master planet. 



Jupiter. 65 

They were the gunboats cutting quick circles, Jupiter 
was the battleship moving majestically in its large 
orbit, never relaxing its hold on these tributary 
vessels. 

Galileo's Exaggeration. The Copernican theory 
had alleged that the terrestrial system, consisting of 
the earth and its satellite, was revolving about the sun, 
the earth in a circle or cycle (for they mean the same) 
and the moon in an epicycle. This was the cardinal 
principle of the Copernican hypothesis. In the early 
part of the seventeenth century, Galileo was its most 
zealous and strenuous protagonist. When, therefore, 
in 1610 he had descried the satellites of Jupiter and 
their mode of motion, be believed that he had now 
at hand a conclusive and compelling proof of the 
Copernican theory. For the Jovian system fulfilled 
the conditions which Copernicus had postulated for 
the earth-moon system. 

But it is now quite clear that the argument was 
one of analogy only, admittedly a striking similitude, 
and yet no more than a similitude. Now analogy 
never constitutes irrefragable proof, capable of satis- 
fying the demands of positive science. In the matter 
of the earth's revolution, scholars were compelled 
to wait until in the period following Galileo's death 
Newton should supply the required stringent proof 
with his law of Universal Gravitation. 

In Galileo's day "there were no direct conclusive 
arguments for the revolution of the earth," wrote 
Fr. Secchi, and Miss Agnes Gierke has added, Galileo's 
discoveries were "brilliantly illustrative, although not 
demonstrative, of the Copernican theory." Let these 
judgments made by irreproachable authorities be 



66 Jupiter. 

kept in mind in any discussion of the celebrated case 
of Galileo. 

A Warrantable Inference. The Galileo case aside, 
our study of Jupiter and its satellites is calculated to 
deepen our conviction of the reign of law in nature. 
Not only in its larger lines but in its smallest details 
the universe is both fashioned and operated according 
to law. It is most nearly likened to a watch or chro- 
nometer, albeit of huge dimensions. Of a truth it is 
nature's timepiece, on which all of man's similar 
fabrications depend for their reckoning and their 
speed. 

The Jovian system is one set of wheels in the great 
cosmic horologe. Study shows that they move and 
turn in perfect order and with absolute precision. 
They exhibit a refinement and delicacy of construction 
that neglects not the smallest detail. No part of a 
watch but evidences the designer's craft; no part of 
the universe but witnesses to the intelligence of its 
First Cause. 



CHAPTER VII. 
THE NATURE OF THE SUN. 

It will not surprise us to learn that almost from 
the beginning of man's contemplation of the heavenly- 
bodies he was led to inquire into their intrinsic na- 
ture. Very early in the history of astronomical 
science curiosity was awakened and speculation 
started as to how the astral bodies were composed 
and what sort of beings they really were. 

Until very recent times, it is almost needless to say, 
the answers to these inquiries could be no more than 
guesses at the truth and vain surmises. The sun and 
stars were too distant to allow close study and detailed 
observation, and the telescope had not yet been 
invented to bring these objects into closer view. 

Ancient Belief. There prevailed among pagan races 
an almost universal belief that the sun and moon and 
planets were supra-sensible beings endowed with 
supernatural powers and, as so many divinities, 
ruling the affairs of men. Even the most en- 
lightened attributed to them a nature utterly unlike 
that of the earth. They dwelt in the upper ether; 
their lightness bore them aloft or sustained them 
afloat high above our atmosphere. By their very 
nature they glided easily from place to place, while 
our earth remained sluggishly at rest. The earth was 

67 



68 The Sun. 

constituted of ponderous dull clay, they were of some 
subtle, intangible substance, wholly unlike everything 
with which we were familiar. Vague as were the 
conceptions of the ancients, it is clear that they were 
persuaded of an utter dissimilarity of nature between 
the earth and these residents of the sky. 

Plausibility of this Belief. Even now we should be 
botmd to cherish similar opinions did we trust to 
appearances alone. For is it not true that the 
celestial orbs pursue lightly their course across the 
blue empyrean like so many incandescent balloons 
inflated with the lightest of gases? And does not 
every solid substance, on the contrary, sink as low 
as possible and fall immediately and rapidly to the 
earth when released in mid-air? 

And is it not true that our earth is of itself dark and 
cold and motionless, whereas the sky's inhabitants 
are forever brilliant with light, glowing with warmth 
and instinct with ceaseless activity? After all, was 
it so extravagant of the ancients to suppose the 
denizens of the firmament to be utterly unlike the 
earth ? Shall we dare charge so mighty a philosopher 
as Aristotle with puerility? 

MODERN STUDIES. 

Advent of Descriptive Astronomy. With the inven- 
tion of the telescope in the first decade of the seven- 
teenth century there was given to men an absolutely 
new source of astronomical information. From that 
event descriptive astronomy dates its birth. Some- 
thing more than mere conjecture will from this date 
be possible respecting the surface features and intimate 



The Sun. 69 

make-up of the heavenly bodies. The telescope will 
reduce markedly the distance of the various objects 
of the solar system, bringing them into closer range. 
What light this great instrument has shed on the 
problem of the sun's nature, we have now briefly to 
review. 

Sun Spots and Their Import. One of the first dis- 
coveries made by Galileo with his newly-found imple- 
ment was that of sun spots, dark patches or areas that 
appear not infrequently on the sun's shining disk. 
In the course of time these sun spots were made the 
basis for a new theory of the sun's nature fully as 
curious and extravagant as was the opinion of the 
ancients. 

It is only a little more than a century since Wilson, 
a Scottish astronomer of repute, announced his 
opinion that the sun is fit for habitation. The part of 
the sun that we normally see is, according to Wilson's 
theory, no more than a surrounding atmosphere of 
intensely white incandescent vapor. Underneath it 
lies the true body of the sun, solid and non-luminous 
like the earth and presumably, like the latter, suited 
to the needs of living beings. 

The argument for the theory rested on the phenome- 
non of sun spots. These were interpreted as being 
rifts or openings in the solar atmosphere, allowing us 
to peer through the sun's gaseous envelope and to 
descry portions of the interior sphere which con- 
stituted the true body of the sun. 

An Extreme Yet Popular Theory. To the other 
extremity of its arc had swung the pendulum of 
thought. From being totally unlike the earth, the 
sun came now to be conceived as its almost perfect 



70 The Sun. 

counterpart. Both were rigid impenetrable globes, 
differing in magnitude alone, and each might be the 
secure residence of living occupants. In physical 
features the sun had been degraded to the level of the 
earth. The mystery of its being was unveiled. No 
longer must it be esteemed of superior essence, light, 
airy and ethereal, but as heavy, compact and rigid 
as the earth itself. What a descent from the proud 
estate allotted it by the older philosophy ! 

Nor was Wilson alone in advocating this now 
rejected theory. Herschel, his contemporary and the 
most famous astronomer of his age, gave to it the 
prestige of his name and the weight of his authority, 
and Arago, the delightful lecturer of the succeeding 
period, followed suit and disseminated throughout 
France the doctrine of the sun's habitability. What 
a surprise to us now to learn that in the first half of the 
nineteenth century this theory was a current teaching 
in the manuals of astronomy ! 

In Medio Stat Veritas. Correct knowledge holds 
a middle way between the two extremes. The sun 
is not totally unlike the earth, nor is it wholly similar. 
In its chemical make-up it resembles the earth to a 
remarkable degree, while in its physical condition it 
is far removed. The ancients were wrong in asserting 
the Sim to be of quite another substance ; but Wilson 
also erred in imagining that the true sun has a su- 
perficial topography assimilating it to the earth. To 
refute these two opposite errors and at the same time 
to pursue an orderly train of thought, one's study of 
the sun's intrinsic nature should be arranged under two 
headings, the chemical and the physical. 



The Sun. 71 



CHEMISTRY OF THE SUN. 



Chemical Make-up of the Sun. It is the business 
of chemistry to study the elemental constitution of 
bodies. With this science as our handmaid we have 
come to learn the ultimate composition of the things 
that are in the earth itself and in its waters and in the 
air by which it is environed. The elements into which 
all terrestrial objects can be resolved are only few in 
number, perhaps not over eighty. Their names and 
classes can be foimd in any good primer of chemistry. 

Now the Sim, unlike the earth as it seems, is, never- 
theless, similarily composed. The spectroscope, a 
marvellous instrument, whose proper use dates only 
from the year 1859, has analyzed the sunlight and 
compared it with the light emitted by the several 
terrestrial elements when rendered incandescent. 
The fruit of this analysis and just comparison has been 
to reveal in the sun's mass a large number of the self- 
same elements that abound upon the earth. 

Spectrum Analysis. Remarkable indeed have been 
the advances of spectrum analysis and wonderful its 
revelations. Incidentally it may be said that no one 
had a larger share in effecting this progress than Fr. 
Secchi, the distinguished Italian Jesuit astronomer. 
How unexpected and curious it was that by this 
science there should be fotmd in the sim some thirty 
or more distinct elements, all of them, with but one 
exception, identical with the earth's constituents. 

It was a triumph of spectrum analysis to show that 
the sun is like the earth even in the materials of which 
it is composed. Away now with the ancient specula- 
tion that the sun is of some strange indefinable sub- 



72 The Sun. 

stance like ether or other suppositious thing. In its 
stead we must adopt the interesting verdict of 
modem science that the sun's mass is constituted of 
the identical materials, the same metals, non-metals 
and gases, out of which the earth is moulded. 

Unity of Nature. More and more as science has pro- 
gressed, it has taught us the community that obtains 
throughout the visible universe. All things obey 
common laws, all exhibit a common plan, all are con- 
structed, as we have just now intimated, of common 
materials. It is one of the highest problems of natural 
philosophy to seek to discover the cause of this perfect 
unity. For us who believe in Christian monotheism 
the problem is already solved. 

Habitability of the Sun. It remains for us now to 
address ourselves to the opposite theory, that of a 
century ago, which arguing from sun spots alleged that 
the nucleus or mass of the sun is a dark body and fit 
for habitation. The inquiry has a certain human in- 
terest, as forming a part of the wider problem of the 
habitability of the heavenly bodies in general. Many 
a pen in recent years has been busy with the question 
of the possibility of life elsewhere than on the earth. 

Considerable headway will have been made with the 
larger problem if we can reach a satisfactory conclu- 
sion respecting the habitability of the sun. For all 
the fixed stars, numbering tens of millions, are in- 
dubitably kindred to the sun in their physical nature, 
and whatever conclusion we adopt anent the sun's 
fitness for habitation must apply equally to the 
multitude of the stars. 



The Sun. 73 

PHYSICS OF THE SUN. 

Its Physical Condition. It is the verdict of Science 
that the sun, while chemically akin to the earth, is 
very unlike it in its physical condition. Of physical 
traits the most important is temperature. All evi- 
dence tends to show that the heat of the sun is so 
intense as to be absolutely prohibitive of the presence 
of corporeal life. Nay more, the probability is that 
nothing, not even the hardest adamantine rock, 
could retain its solid condition if brought to the sun, 
but must perforce be resolved by the excessive solar 
heat into a molten or even gaseous state. 

In an earlier number of this series attention was 
directed to the vast quantities of heat that our planet 
derives from the sun. And by an argument from effect 
to adequate cause, it was there contended that the 
sun itself must be a seething mass of fire of far greater 
volume than the earth. For the earth receives only 
its quota of the sun's radiant energy, the fraction being 
less than one two-billionth of the whole. The rest 
is radiated to all parts of space in amounts capable 
of vivifying two billion planets set at the same 
distance as our own. Yet, nothwithstanding this 
enormous output of thermal energy, the original power 
of the sun has remained undiminished, as far as we 
can judge, throughout historical time. What tremen- 
dous play of thermal forces is thus argued for the 
body of the sun! 

Direct Evidence of Activity. But we are not con- 
fined to indirect argument for proof of the mighty 
activity at play within the solar boundaries. Sun 
spots and solar eclipses both afford us direct and 



74 The Sun. 

observational proof. By whatever theory sun spots 
be explained, they are surely to be regarded as solar 
disturbances of vast extent. The very fact that they 
are visible from our distance implies that they affect 
vast areas. Over and over again they reach a 
diameter of eight thousand miles, large enough, there- 
fore, to engulf the earth. At times the dark area 
extends one-eighth way across the sun's disk, be- 
tokening a diameter of a hundred thousand miles. 

Moreover, these solar eruptions, tornadoes, or 
whatever else they be, are far from being infrequent 
in occurrence. There are years, it is true, when they 
are at a minimum and but few will be seen. But in 
maximum years hardly a day passes without the 
appearance of some sun spot, and on many days two, 
three, or more can be counted. 

Without committing ourselves to any particular 
theory of the origin of these phenomena, we are yet 
constrained to admit that they denote solar activity 
carried on on a stupendous scale. For the sun spots 
are not stationary or tranquil. They break forth 
suddenly, enlarge to dimensions more than terrestrial, 
combine or divide, change shape and form and 
disappear, all in a few days' or weeks' time. We have 
to strain our imaginations to fancy the huge quantities 
of matter thus set in motion and the rapid velocity 
their particles attain. 

Solar Eclipses. Of a piece with sun spots are the 
phenomena witnessed on the occasion of a total solar 
eclipse. When the sun's luminous disk is just 
covered by the interposition of the moon and thus 
hidden from our view, there appear outside the rim 
of the eclipsed body two circles of light which trans- 
form the eclipse into a spectacle of great beauty. 



The Sun. 75 

The inner circle or ring is called the chromosphere 
or sphere of color, taking its name from the brilliant 
crimson or scarlet light with which it is suffused. 
The outer is called the corona or crown. Pearly in 
color, it is a reminder of the nimbus or halo with 
which the heads of saints are encircled in Catholic 
works of art. Of high esthetic interest are these two 
envelopes of color, the one rich and gorgeous, the 
other delicate and elusive, appearing at the sun's 
margin on the exceptional occasion of a total eclipse. 

The Chromosphere. But they are of astronomic 
interest as well, for they supply new and independent 
evidence of the sim's activity. From out the chromo- 
sphere, itself of medium thickness, shoot forth great 
flames of the same scarlet or crimson color to a height 
of tens of thousands of miles. Just as tongues of 
flame mount up from furnace fires to the tops of tall 
chimneys and appear surmounting them, so from the 
chromosphere arise these solar tongues of fire similar 
in kind but by comparison gigantic in reach and ex- 
tent. After reading of these huge projections of col- 
ored fire of changing form and size, who can doubt 
that powerful volcanic forces are at work in the sun, 
that some mighty Vulcan there keeps his forge, the 
source of the energy which these columns make mani- 
fest? 

The Corona. In the corona, too, the stm's outer- 
most appendage, are signs of activity and change. 
In no two eclipses is the corona quite the same. Its 
boundaries vary and with them its average depth. 
Now the halo is of wide circumference, again it has 
shrunk to a comparatively narrow circle of pearl- 
colored light. At times there radiate from it far- 
reaching streamers stretching many millions of miles. 



76 The Sun. 

The detailed phenomena of the corona are naturally 
most elusive, for this envelope is composed of the light- 
est and rarest of gases. It is like the upper regions of 
the earth's atmosphere, the theatre by the way of the 
not dissimilar phenomena of the northern lights. But 
the corona's continual changes and its wide-extending 
streamers are signs of restlessness and of the eager 
play of physical agencies pursued on a scale to which 
the earth offers no parallel. 

The Application of These Scientific Facts. Thus the 
sun itself tells the story of its own intrinsic activity. 
Through sun spots and eclipses it furnishes internal 
evidence that it is veritably a globe of fire, penetrated 
through and through with heat no solid substance 
could withstand, still less any living organism could 
for an instant endure. No plant or animal could sur- 
vive for the fraction of a minute transported to the 
sun. Its extreme heat would be fatal to the stoutest 
organism. How wonderful it is that the sun, thus 
pitiless of life at its own surface, should be designed 
and adapted to foster and maintain life in happiest 
conditions at the surface of the earth ! How wonder- 
ful is nature even in its antinomies! 

Of itself destructive and overpowering, the sun's 
energy is so tempered by the time it reaches the earth 
that it lights without blinding, heats without consum- 
ing, and makes for the health and growth of the count- 
less vital organisms that people the earth. Can 
chance or blind force account for such a benign dis- 
pensation? As well say that blind chance could have 
checked and harnessed the wild torrential forces of 
Niagara and bent them, as they have now been bent, 
to the service of man. 



CHAPTER VIII. 
HABITABILITY OF THE PLANETS. 

We have seen that there are excellent and con- 
vincing reasons for believing that the sun is quite 
unsuited to be the residence of living beings. The 
same can be affirmed with equal certainty of the fixed 
stars, which, it will be observed, constitute an over- 
whelming majority of the visible heavenly bodies. 
Their likeness of nature to the sun both chemical and 
physical has been well established in modem times, 
and the conclusion is therefore forced upon us that 
they cannot be the abodes of life. 

The writer wishes that something equally positive 
on one side or the other could be affirmed respecting 
the habitability of the planets, the bodies which make 
up the second grand division of the celestial system. 
But it is a subject in which categorical assertions 
whether affirmative or negative appear to outstrip 
the evidence. Nevertheless, whatever may be the 
hope or despair of attaining definite results, the prob- 
lem is surely worthy of consideration, if for no other 
reason than that it continues to engage the thoughts 
of some of our best workers in the field of astronomi- 
cal science. 

Preliminary Remarks. At the very outset, distinc- 
tion ought carefully to be made between the two 

77 



78 Habitability of Planets. 

separate though alHed questions of the habitability of 
the planets and their actual habitation. It is one 
thing to ask if the planets are suited to be the abode 
of life, it is quite another to ask if they are actually 
inhabited. There may be valid reasons for believing 
that the planets are suited to contain living occu- 
pants, but to infer therefrom that they actually con- 
tain living species would be illogical and, in the ab- 
sence of pertinent evidence, gratuitous. 

This division of the problem into two parts being 
premised, it is plain that the first offers more hope 
of solution than the second. The planets are not so 
distant from us but that we can learn much about their 
physical constitution and hence their aptness for con- 
taining living forms. On the other hand, they are 
quite too distant to bring such living forms, indi- 
vidually at least, within the scope of our vision even 
when aided by the most powerful telescopes. At the 
most we can expect only indirect evidence of the 
actual occurrence of life in other worlds than ours. 

GENERAL THEORIES. 

Advocates of Habitability. It is frankly to be ad- 
mitted that a goodly array of names could be quoted 
in favor of the belief that other worlds than our earth 
are fit for habitation. As we should expect, these 
names belong almost entirely to the last three centu- 
ries, starting from the period of the establishment of 
the heliocentric theory by Copernicus. 

The degradation of the earth to an inferior rdle in 
the drama of cosmic activity and the knowledge of its 
inferior size, led many to conclude that it was highly 



Habitability of Planets. 79 

improbable that our planet alone could be the habitat 
of living species. It was not unnatural that with 
their larger outlook on space the astronomers of the 
seventeenth century should conceive as by a first im- 
pulse the thought that there might be a plurality of 
inhabited worlds. From this century, therefore, we 
find quoted as defenders of the theory such respect- 
able names as Tycho Brahe and Kepler, Newton and 
Bentley. 

Evolution Theories. More recently other scientific 
hypotheses, less certain though they are than the 
Copernican, have strengthened in the minds of many 
scholars the presumption that life occurs in distant 
and remote parts of space. The Nebular Hypothesis 
of Kant and Laplace, originating in the latter half of 
the eighteenth century, pictures the earth as having 
evolved only in comparatively recent times from a 
primitive nebula, which was perforce destitute of 
life. Men would naturally inquire, then, if during the 
long centuries that the earth was being moulded there 
could not have existed life on other globes which were 
in a more finished state. For in the absence of this 
assumed fact, there must have been an initial period 
of untold length in which the entire universe was 
utterly devoid of corporeal life. 

Influenced by such considerations, a very large 
number of astronomers of the early nineteenth 
century enrolled themselves on the side of what we 
may call the habitation theory. The list includes 
such representative astronomers as Laplace, the 
Herschels, father and son, Chalmers, Arago, Brewster, 
and Mitchell, the last being the founder of the first 
observatory in the United States. 



80 Habitability of Planets. 

Organic Evolution. Finally, the theory of organic 
evolution especially when pushed to the extremes 
given it by the ultra-Darwinians, is for its advocates 
absolutely convincing of the possibility and prob- 
ability of the presence on other globes of living occu- 
pants. For extreme evolution reduces to the van- 
ishing point the distinction between life and the non- 
living, and finds throughout all nature the essential 
prerequisites for the genesis of living forms. 

It occasions no surprise, then, to find Haeckel and 
all others of the ultra-Darwinian school on the side of 
the habitation theory. On worthier grounds as we 
esteem them, other recent scientists, as Proctor, 
Flammarion, and Percival Lowell, have expressed 
their conviction that other bodies in the universe 
besides the earth have been favored with the honor 
of containing living residents. 

A Preliminary Answer. Putting aside for the 
present the opinions of the trio just mentioned, we 
must take exception to the general line of argument 
that influenced all the earlier advocates of the habita- 
tion theory. If other worlds are not inhabited, asked 
they, what is then the purpose of their existence? 
Are they not as so many wastes and desert lands of 
no conceivable utility? And in the primeval period 
before the earth was formed, if the whole cosmos was 
without life, what useful purpose did it subserve? 

The argument implies that the world can have no 
other adequate purpose than to support life, that in 
its every period and in every considerable portion of 
its space there should exist living forms to which the 
merely material elements shall minister. But this 
claim while specious is gratuitous. Besides the 



Habitability of Planets. 81 

gratification of living creatures the world may have 
other purposes only partly comprehended by us. To 
give external glory to the Creator through the mate- 
rial manifestation of His power and intelligence, 
formed a sufficient purpose for the universe even in 
the first stages of its existence. 

An Ultimate Purpose. Ultimately one of its 
purposes was, as the facts show, to minister to the 
needs of living beings and especially of man. Wide 
as space is, there is no part of it that does not make 
fuller the life of man. The most distant worlds engage 
his thought and compel his admiration. The distant 
past with its primeval chaos evolving into order and 
harmony, challenges his best powers of thought to 
unlock the hidden processes of the world's develop- 
ment and enlarges incalculably the purview of man's 
mental life. Sufficient purpose, then, there may be 
in remote worlds and remote eras even if destitute 
of life. As well doubt this as deny that the desert 
lands of Arizona or the Sahara or of the polar regions 
retain yet a sufficient purpose. 

In any case, this argument of purpose is in great 
measure contradicted by the facts. For all the fixed 
stars, numbering tens of millions, are physically of 
the same order as the sun, all of them globes of fire 
and none of them, therefore, suited to be the dwelling- 
place of life. Here, then, are fifty million created 
globes which according to the proposed argument 
would have no sufficient reason for existence and yet 
which actually exist. 

A Second Speculation. The problem of habitability 
becomes more difficult, however, when narrowed 
down to the planets. For here we are dealing with 



82 Habitability of Planets. 

bodies whose general nature assimilates them to the 
earth. They like the earth are, for the most part, 
firm and solid spheres, luminous only because of the 
sunlight they reflect and not in virtue of their own 
fiery incandescence. One's first impulse is to con- 
clude that in view of the earth's well-known fitness 
for habitation, all its sister spheres, the planets, must 
be habitable also. Many a tyro in astronomy be- 
lieves, undoubtedly, that the planets as a class are 
fitted to become the abodes of life. 

But here again the argument runs too fast. With 
maturer knowledge the tyro will learn to halt before 
such sweeping generalizations. A fuller science will 
bid him subject to tests the individuals of the group, 
to learn if this planet here and that there fulfill the 
conditions required of them as habitable bodies. The 
outcome of his inquiry will be to glean that few of the 
planets if any are like the earth in its aptness to en- 
gender and maintain organic life. He will then 
reconstruct his theory, and cease to assign habitability 
as a necessary attribute of the members of the 
planetary system. 

SPECIFIC REQUIREMENTS. 

Conditions Needed for Life. There is a branch of 
knowledge whose special province is the living world, 
the science of biology. To it must the astronomer turn 
for the preliminary data needed in the solution of 
his present problem. From the biologist shall he learn 
the necessary material prerequisities of organic life. 

Opening a standard text-book of biology, we find 
that for corporeal life there are demanded, first of all, 



Habitability of Planets. 83 

certain definite chemical elements. Carbon, oxygen, 
hydrogen, and nitrogen are substances so urgently 
required that throughout the whole range of the plant 
and animal kingdoms there is not a single species or 
form without them. 

Let it be admitted at once that this first required 
condition is fulfilled by all the planets. As has already 
been noted, nature throughout her length and 
breadth has apparently made use of the same con- 
stituent materials for the construction of all her unit 
spheres, suns and planets alike. There is excellent 
reason to believe that any one of the planets chosen 
at haphazard, whether Jupiter, Venus, or any other, 
would reveal within its mass the raw material needed 
to form living protoplasm. 

A Proper Atmosphere. There is need further of a 
proper atmosphere or gaseous envelope, on which 
plants and animals may draw for their subsistence. 
All living forms breathe in one manner or another. 
From the atmosphere plants take the carbonic acid 
gas that shall be converted into the carbon of their 
woody fibre. At the same moment animals extract 
from the air the oxygen so abundantly needed for the 
refreshment of their blood and tissues. Without a 
medium containing carbonic acid gas no plant life 
could exist; and no animal life without an added 
admixture of oxygen. 

Failures Under This Requirement. It is certainly 
to be accentuated that the vast majority of the com- 
ponents of the solar system fail to meet successfully 
this second test. Indeed none of them meet it except 
the eight greater or major planets. The satellites or 
secondary planets, over twenty in number, are all too 



84 Habitability of Planets. 

feeble gravitationally to retain at their surface a 
proper atmosphere. To them must also be added as 
similarly restricted the whole group of minor planets 
or asteroids, a force of five hundred diminutive bodies 
occupying the zone between Mars and Jupiter. 

True planets all of these are whatever be their 
distinguishing names. For they are solidified bodies 
shining by reflected light. Yet no one of them is 
enveloped in an atmosphere suited to the maintenance 
of life. The absence of all trace of atmosphere from 
the surface of the moon has long been a well-established 
fact of observational astronomy. And the moon is 
typical of the entire group above enumerated. 

The writer is not unaware of Wm. Pickering's recent 
contention that the moon shows certain signs of the 
presence of vegetative growth. But the theory seems 
to rest, with due respect be it said, on slight and 
insufficient evidence, and has thus far failed of 
acceptance as an accredited fact. 

Aqueous Element Needed. A third and one of the 
most imperative of all requirements for habitability 
is the provision of water at least in the form of humid- 
ity or moisture. The most indispensable require- 
ments of living nature are the things which on this 
earth of ours have providentially been made the 
cheapest, a fertile soil, air and water. The last of these 
is so large and so necessary an element in all living 
protoplasm that without it life would be impossible. 

That all the greater planets save one fulfill this 
requisite of a competent water supply, is within the 
bounds of likelihood. The probable exception is 
Mercury, exceeding but little the moon in magnitude 
and hence to be esteemed like the latter in its physical 



Habitability of Planets. 85 

conditions. On the moon's surface there is now no 
sign of change betokening the present erosive action 
of aqueous agencies. What were formerly called 
the seas or oceans of the moon are now believed to 
be great arid plains, of perhaps darker-colored rock 
than the rest or lying so flat and low that they receive 
less of the sun's illumination. 

It may well be that as with the moon so with 
Mercury its original covering of water has evaporated 
into space, leaving the planet in each case a barren and 
lifeless waste. But the case of Mercury is exceptional. 
The superior magnitude of the other chief planets 
seems to preclude the chance that they have lost 
entirely the oceans and rivers and lakes with which 
they were originally engirdled. 

TEMPERATURE TEST. 

Life-Sustaining Temperatures. Finally, tempera- 
ture or degree of heat has, according to all biologists, 
a most important bearing on the maintenance of life. 
There is a normal or middle temperature at which life 
flourishes best, exhibiting then its richest fertility. 
There are extremes of heat and cold no organism can 
withstand. The range varies indeed with different 
species, so much so that it is impossible to give figures 
that will apply to all alike. For man the optimum or 
ideal temperature is not far from 65° F., as our own 
experience tells us, and as the thermometer scale 
records. 

To the temperate zone of the earth drift naturally 
all the dominant races of men because there ideal 
climatic conditions are so nearly realized. Indeed if 



86 Habitability of Planets. 

a calculation be made for all the geographical zones 
through all the seasons, the average warmth is found 
to be, according to Percival Lowell's latest book, in 
the neighborhood of 60°. So well suited is our planet 
to be the dwelling-place of man. 

Other Forms of Life. For other species the average 
optimum temperature i- given by biologists as a little 
above 90°. A sustained accent to 122° is fatal to all 
species in the adult stage and descent to 32° is fatal to 
many. The germs or seeds of life, to be sure, can 
transcend these limits with safety, but it should be 
remembered that they are the products of life rather 
than its origins, and it still remains exceedingly doubt- 
ful if life could start into being outside the range given 
above. Moreover, even germs succumb to still higher 
or lower temperatures, as is evidenced in our modern 
practices of sterilization and refrigeration. 

Further, relation between thermal conditions and a 
competent water supply deserves to be emphasized. 
Lowered to the state of frost and ice, or raised to the 
condition of steam, water would be unserviceable as 
a medium for life. A planet, then, whose constant 
temperature is either below 32° F., the freezing point 
of water, or above 212°, its boiling point, could not be 
admitted to be a fitting habitat for organized living 
beings. 

Outer Group of Planets. It remains to apply this 
temperature test to the seven major planets, our 
present subject of study. How many of them fall 
before it, is matter for surprise. Astonishment 
begins when examination is made of the outer group 
of planets, comprising Jupiter, Saturn, Uranus and 
Neptune. These are the giants of the planetary 



Habitability of Planets. 87 

system, the least of them thirty-two thousand miles 
in diameter, and the greatest of them, Jupiter, almost 
ninety thousand. 

They have their own independent glories, each of 
them endowed with special features of esthetic and 
astronomic interest. But not one of them could 
afford a foothold for living beings. Their heat is too 
intense. That we do not know their exact degree 
of surface temperature is of small account. We know 
enough to affirm that it is prohibitive. 

Their Semi-Molten State. Their low specific gravity 
mathematically ascertained tells plainly the story 
of their physical condition. Their density averages 
one-fourth, or even less, that of the earth. Rock for 
rock, their constituent parts are expanded to four 
times the volume of the corresponding constituents 
of the earth. Excessive heat alone can account for 
such expansion. 

Hence it is that all astronomers agree that these 
four planets are still in a semi-molten condition, not 
yet sufficiently cooled down from their primeval 
igneous state to have acquired the form and density 
of rigid solids. Miss Gierke has described Jupiter as 
a fluid globe, a semi-sun, showing no trace of a solid 
surface. Whence also Sir Rober Ball justly concludes, 
'T see no likelihood that Jupiter can be the home of 
any life whatever." Jupiter may fairly be taken as 
typical of all the components of the outer group. 
On no one of them would organic life have better 
chance of survival than in the crater of a lava- 
belching volcano. 

The Inner Group. Of the inner assemblage, again 
of four components, Mercury is the first in order of 



88 Habitability of Planets. 

distance from the sun. The paucity of its atmosphere 
and its lack of water in the liquid form would seem 
to preclude the possibility of this planet's being in- 
habited. 

If Mercury rotates so slowly as to keep one hemi- 
sphere turned always towards the sun, a fact which 
Miss Gierke accepts as probable, then on neither of 
its sides could fluid water be found. On the one 
hemisphere, that of perpetual winter and night, it 
would be transformed into solid ice; on the other, 
that of everlasting summer and sunlight, into the state 
of vaporous steam. On this basis Miss Gierke has 
seen fit to write that * 'Mercury is, according to our 
ideas, totally unfitted to be the abode of organic life." 

The Second Planet. With Mercury is probably to 
be associated Venus, though it must be admitted in 
fairness that here the fact of slow rotation is less 
surely ascertained. With proper caution Miss Gierke 
couples together these kindred planets, saying: 
"With due reserve it may be added that Mercury and 
Venus have thus apparently been rendered unfit to be 
the abode of highly developed organisms." 

Apart from all theory and mere probability, there 
stands the certain fact of the proximity of these two 
planets to the sun. On them descends a far larger pro- 
portion of solar energy than the equable amount that 
our planet receives. On Mercury the solar rays would 
beat down six times more fiercely than on the earth, 
an excess that would surely be destructive of life. 
Even Venus' share in the solar radiance is double 
that of the earth, begetting an increase of temperature 
which, theoretically at least, would make all life 
impossible. 



Habitability of Planets. 89 

The Planet Mars. There remains, then, but one 
globe of all that constitute the solar system, about 
which the question of habitability can be mooted 
with profit, in the sense of hope of an affirmative 
result. This is the planet Mars, one of our nearest 
neighbors in space, and of all the major planets the 
most favorably situated for observation. Its case 
is of such present interest that it deserves to be studied 
separately and in some detail. 

Let it be conceded from now that Mars presents 
richer signs than any other planet of the power to 
support life in some of its simpler forms. This is far 
from conceding, however, that there is proof that it 
could support human life or any vital form akin to it. 
To Mars, as well as to all other worlds within our ken, 
applies the stricture of Sir Robert Ball, "Probably 
man could not exist for five minutes in any other 
planet or body of the universe, nor any being nearly 
resembling man." 

The Earth*s Ascendancy. The net result of our 
inquiry thus far has been to learn that habitability 
or the power of a created globe to support life, so far 
from being a common thing in nature, is a decidedly 
rare phenomenon. The power may not be quite 
exclusive to the earth, but within the solar system at 
any rate it is almost so. And as far as bears on 
human life, the earth's proud prerogative seems to 
be absolutely unique and unshared by any other 
body. Thus the earth, displaced from its pre- 
eminence of position in space by the establishment 
of the Copemican theory, retains still its pre-eminence 
of dignity and importance as being the only residence 
of life, at least in its highest and worthiest forms. 



CHAPTER IX. 
THE PLANET MARS. 

The discussion of the habitability of other worlds 
reaches its climax in the planet Mars. All other 
heavenly bodies within our observation are now to 
be regarded as eliminated, if not indubitably from the 
category of habitable worlds, at least from the field of 
profitable discussion. Before one or another test 
have fallen whole groups that were formerly deemed 
likely subjects of inquiry, the fixed stars, the satellites, 
the asteroids, and finally the major planets, with 
the single possible exception of Mars. Whatever 
our preconceptions may have led us to expect, all the 
evidence is against the likelihood that any one of these 
numerous bodies is possessed of living occupants. 

But the case of Mars is not to be so readily dismissed. 
Indeed, it remains for us to see if it is to be dismissed 
at all. For many decades past, books of astronomy 
have given to Mars the distinction of being more 
nearly like the earth than any other celestial object 
and more worthy to be credited with the character of 
habitability. Even half a century ago speculation 
was rife as to what might be the nature of the creatures 
that people the ruddy planet. 

The Canals of Mars. It is now a little more than 
thirty years since Schiaparelli, an Italian astronomer 

90 



Habitability of Mars. 91 

of note, announced his discovery of certain markings 
on Mars, to which he gave the name of canals. Canali 
he called them in the Italian tongue, the name mean- 
ing waterways of any sort whatever, whether artifi- 
cial or natural. But translated into our vernacular, 
the term conveyed at once the impression of artificial 
channels designed and executed by intelligent agents. 
Here, then, according to the world's misconception 
of Schiaparelli's meaning, were clear signs of intelligent 
life on Mars. 

Careful astronomers pointed out that these lines 
crossing the planet's disk could not possibly represent 
water-courses artificially constructed. For the least 
of them, it was urged, must be fifty miles in width 
to be visible in our telescopes, and it was preposterous 
to suppose that intelligent beings had gone into the 
business of canal construction on so enormous and 
futile a scale. 

Prof. LowelPs Findings. Even the recent com- 
putations of Percival Lowell, to the effect that some 
of the canals are as low as ten miles in width, do not 
save the situation as bearing on the artificiality of 
these reputed waterways. For the nation that would 
set to work to make an aqueduct ten miles broad 
would appear as foolish in the world's eyes as the 
ancient projectors of the tower of Babel. 

Not that Lowell himself judges these dark bands 
to be aqueducts. Be it added at once that nothing 
is more foreign to his thought. Some fifteen years 
ago he conceived a new theory of the so-called 
canals, which, besides being of itself attractive, re- 
moves at once the difficulty of the canals' exorbi- 
tant width. 



92 Habitability of Mars. 

His Theory. His theory of these markings is that 
they are broad tracts of vegetative growth, forests 
or fields of grain, which flank central waterways of 
moderate width, the latter, however, being of artificial 
origin. The verdure, which he supposes the dark 
lines to signify, requires water for its sustenance. 
It will grow and abound only along the banks of 
rivers. But on Mars it grows so regularly, along 
definite lines measuring hundreds of miles in length 
and running always straight as a die, as to connote 
and demand artificial control of the streams which 
nourish it. 

The theory has been so insistently urged by Lowell 
that it has forced itself on popular and scientific 
attention alike. And it is the commonest of ex- 
periences nowadays to read in journals of all sorts and 
qualities, references to the Martian inhabitants, 
always, of course, represented as highly intelligent 
and man-like, for this is the only sort of inhabitants 
that most persons care anything about. 

It seems a pity to be compelled to subject so entic- 
ing a theory to the cold analysis of scientific scrutiny. 
Imagination has its part to play, undoubtedly, in the 
discernment of truth and is not to be esteemed the 
least of our faculties. Its worth ceases, however, 
when its use is misapplied. 

Facts About Mars. The planet which takes its 
name from the Greek god of war, is unquestionably 
more like the earth than any other globe we know. 
It is somewhat less than the earth in size, its volume 
one-seventh and its mass one-ninth the latter 's, but 
as cosmic bodies are reckoned, this disproportion is 
not large. It has its day and night, differing in 



Habitability of Mars. 93 

length from ours only by nainutes and not by hours. 
It has its seasons and its year, each double the earth's 
in duration. 

As a consequence of its somewhat greater distance 
from the sun it receives but one-half as much of solar 
heat and energy. Theoretically this would reduce its 
temperature below the point at which life could sub- 
sist. But there may be compensating circumstances 
that modify the theoretical calculation, and as a mat- 
ter of fact the evidence of melting ice and running 
water on Mars argues a higher temperature and one 
agreeable to living forms. In size, seasons, alterna- 
tion of day and night, and degree of heat, it is not 
so disparate from the earth but that it could safely 
be imagined the abode of life. 

Other Signs of Habitability. An earlier study taught 
us the transcendent importance for life of an atmos- 
phere and water. There are evidences of both on 
Mars. Its atmosphere, as scientists agree, may well 
combine the essential ingredients of ours, reduced 
ninefold, however, in density. Water is denoted by 
the white polar caps, which melt away as summer 
advances, only to form anew in the succeeding winter. 
No longer, as formerly, is the provision of water 
esteemed to approach the earth's in magnitude. The 
polar fields of ice and snow, extensive but shallow, 
are the planet's only reservoir and means of irri- 
gation. 

A fair review of these facts and conditions suffices to 
persuade us that Mars is in all likelihood habitable 
for some forms of life. Here at last we have met with 
the conditions we were seeking. This planet is the 
only body in the universe outside the earth of which 



94 Habitability of Mars. 

we have any positive or goodly reason to affirm fitness 
for habitation. 

Does Habitation Follow? To jump from this, 
however, to the conclusion that it must be inhabited 
is an offence against good logic. The extreme fertility 
of the earth misleads us into believing that all soil 
which can will teem with life. But the fertility and 
after-growth of life is the easiest thing about it to 
explain. The hardest is to say how and where it got 
its start. Mere inert matter never produces it, so 
says all the evidence, and so report the scientists. 
Unless God by a special creative act puts life 
upon a planet, we believe that it will not there 
be found. 

Lowell believes otherwise. He clings tenaciously 
to the theory of spontaneous generation, a doctrine 
we had supposed pretty well abandoned by prudent 
scholars. He holds that a planet, properly conditioned, 
will infallibly produce life by its very nature and as an 
inevitable incident in its development. Were life 
of a piece with volcanic activity, we could agree with 
him. But persuaded as we are that life is a unique, 
distinct, mysterious phenomenon, inexplicable on any 
mere mechanical or physical theory, we cannot agree 
that a planet as such is bound some day in its history 
to beget living forms. 

Physical conditions alone will not suffice. A little 
reflection will remind us that the abundant living 
things of earth come not from the latter as a mere 
planet careering through space, nor from its water 
and atmosphere, its carbon, oxygen and the like, 
necessary as are all these, but always and solely from 
pre-existing life. And the beginnings of terrestrial 



Habitability of Mars. 95 

life we believe with good reason to have come from 
a special creative act of God. 

Evidences of Habitation. But will not God have 
created life on Mars ? Of his purpose we cannot know. 
But perhaps there is actual evidence at hand. Lowell 
says there is. He finds evidence of life in two forms, 
of vegetative growth along the canals and at their 
junctions, and of intelligent life in the systematic 
planning of the canal system. 

Possibly the first holds ; the dark lines may repre- 
sent vegetation. He has studied them and their 
changes more than any other man and is most com- 
petent, perhaps, to make an inference. He has yet 
to explain, nevertheless, how with such an impover- 
ished water supply three-eighths of the planet's 
surface can still be the seat of vegetation. For other 
than as vegetation areas, there is given in his book 
no explanation of the great dark spaces which cover 
almost half the surface. And if these dark spaces 
stand not for vegetation, why any more the dark 
narrow lines which are of the same hue? 

Activity Intelligent and Unintelligent. But vegeta- 
tive life conceded, issue may fairly be taken with 
Mr. Lowell's contention that on Mars exists a higher 
order of life in the form of intelligent corporeal beings. 
His argument rests on the perfect regularity of the 
so-called canals. These run for hundreds and even 
thousands of miles along perfectly straight lines. 
No natural force, he claims, can account for such 
directness. The only hypothesis that will explain 
them adequately is that they are irrigation tracts 
outlined and executed by intelligent beings, who 
take this means of spreading the sparse waters of 



96 Habitability of Mars. 

the melting polar caps over an otherwise arid and 
desert globe. 

Delightfully fanciful as is this hypothesis, the 
objections to it are numerous and considerable. We 
are asked to believe that man or his Martian counter- 
part has covered the whole surface of Mars with a 
most intricate and complicated network of waterways 
and sluices. The similar irrigation devices on the 
earth are to be numbered in units; on Mars they 
number hundreds. Over four hundred have thus far 
been coimted. Truly the Martian engineers have 
been busy with the labor of canal construction ! 

Formidable Objections. The least of the discovered 
canals measures two hundred fifty miles in length, 
the distance separating Boston and New York. The 
greatest extends four thousand miles, and would 
therefore traverse our continent from ocean to ocean. 
With us it is no easy feat of civil engineering to carry 
a city's water supply from a distance of fifty miles. 

The Martian canals run straight as a ruler, with 
never a turn to right or left. There is never a detour 
to this side or that for the finding of more workable 
soil or rock, or for the rounding of the Martian hills 
which Lowell concedes to exist. Where on this earth 
could be found an aqueduct or railway or street or 
any other artificial road thus pursuing its course 
evenly without detour for ten miles, not to say four 
thousand? The canals are too perfect to be of human 
origin. Four hundred thousand miles of aqueducts, 
built each of them without a turn, this is, we opine, 
too much for human credulity. 

It is scarcely necessary to advert to other facts which 
Lowell leaves unexplained. The doubling of the 



Habitability of Mars. 97 

canals, a phenomenon first perceived by Schiaparelli, 
occurs, according to Lowell's estimate, in almost one- 
eight of the total number. It is a singular fact and 
would seem to be an unwise duplication that so many 
conduits should have been laid side by side in mathe- 
matically parallel lines. Of this strange phenomenon 
Lowell's latest and maturest book does not venture 
to offer an explanation. A further singularity, also 
left unsolved, is the continuance of the canals not 
merely over parched deserts, but through the dark 
areas which are assumed to be regions still supplied 
with vegetative life. 

Silence of Astronomers. Creditable as has been 
Mr. Lowell's exploration of the ruddy planet, un- 
equalled indeed by that of any other observer, we 
know of no astronomer of repute and distinction who 
agrees with the most important of his inferences. 
Schiaparelli was attracted by the vegetation theory 
as an explanation of the canals. But he is not quoted 
as having acknowledged their artificial character. 
Wm. Pickering of Harvard is also disposed to accept 
the dark spaces and lines on Mars as indicative of 
plant life. But he believes the lines followed by this 
vegetation to be natural clefts in the Martian surface, 
like those of which our moon offers many instances. 
For the rest, who among astronomers of name and 
note can be quoted on Lowell's side? 

Earth Without a Rival. The criticism we have 
made is not the fruit of bias or prejudgment. It is 
consistent with and accompanied by a profound 
appreciation of Lowell's astronomical labors, un- 
paralleled in this particular field. But his interpre- 
tation of the facts amassed taxes our faith too sorely. 



98 Habitability of Mars. 

As we interpret the evidence, it avails only to prove 
the possibility of some low orders of life on Mars. It 
falls far short of witnessing to human occupants. 
Sweeping the universe with our mental vision, it seems 
to us not yet disproved that in the mysterious plan 
of Providence the earth alone has been designed and 
framed to be the suitable residence of intelligent 
corporeal beings. 



CHAPTER X. 
THE SIDEREAL WORLD. 

Hitherto our considerations have been limited for 
the most part to the members of the solar system, 
comprising the sun, the planets, and the satellites. 
There are excellent reasons for extending now the 
range of our investigations by delving a little into 
the larger subject of sidereal astronomy, the study of 
the fixed stars. 

To the Catholic, believing firmly in the fact of the 
world's creation, there is no body in the universe from 
the least to the greatest, from the nearest to the most 
remote, that is altogether without interest. All are 
the products of God's handiwork, all have felt the 
impress of His creative wisdom and love. We cannot 
imagine, with reverence be it said, that the Godhead 
is indifferent to any single object which He has called 
into being. No more can they who believe in Him, 
remain indifferent or be content to abide in ignorance. 

Astronomy Religious and Irreligious. It is time, 
moreover, to rescue the science of the heavens from 
the sad condition into which with too many it has 
fallen in these later days. Too long has the study of 
the stars been in many quarters divorced from the 
study of religion. Many an astronomical manual 
could be named which from cover to cover contains 

99 



100 The Stars. 

no mention of the Deity. How unlike the sacred 
books of the Hebrews, which whatever their astrono- 
mical defects, never ceased in prose and verse, in 
hymn and parable, to ascend from creature to Creator, 
on every page and in every canto rendering praise and 
glory to the acknowledged Author of the imiverse ! 

To restore astronomy to its former more honorable 
role is indeed one of the purposes of these essays. 
They are intended, as far as they may, to annul the 
long-standing divorce between the astral and the 
divine science. They start from the conviction that 
astronomy, properly pursued, is calculated of itself 
and in all its parts not only to refine the mind, but to 
exalt our concept of the Godhead. For the invisible 
things of God, His eternal power and divinity, are 
known from the visible things which He has made. 
(Romans i, 20.) 

Lessons of the Stars. Something of this mood 
must steal upon us whenever of an evening we lift 
up our gaze above the lowly earth and look aloft to 
the nocturnal sky studded with its myriads of stars. 
There they abide, those flashing diamond points of 
light, set against a dark unfathomable background. 
Nowhere in nature can be found a^more perfect symbol 
of serenity and repose. 

In its hour of disquietude or distress, the soul of 
man can find assuagement and tranquility in the con- 
templation of the heavens, with their spectacle of 
perpetual calm unbroken by the vicissitudes of earth 
and the tumult of warring passions. There is no 
tumult in the heavens, but all is steadfast calm, an 
image of the unaltered and unruffled peace that marks 
the life of the eternal God. 



The Stars. 101 

Symbols of Eternity. And in their own degree they 
image eternity as well. At tinaes as we gaze upwards, 
there crosses our mind the thought that the same 
constellations which now look down on us have kept 
their faithful watch over all the multitudinous 
successive events of human history. They have seen 
dynasties and nations come and go. They have looked 
down at midnight on the pitched tents and sleeping 
camps of a Napoleon, a Charlemagne, a Caesar, an 
Alexander. Abraham, father of the faithful, watching 
his flocks by night, beheld on high the same canopy 
bedecked with the same star-groups that now with 
unaltered configurations look down upon us. 

Go back as far as we may in human history, to its 
cradling in the Far East, already in that distant past 
these self -same stars were at their posts, bright, 
serene, and fresh as now. Their youth and vigor is 
more than that of the eagle, it remains unimpaired 
throughout all the eras of which man has record. 

From the mere viewpoint of time, how insignificant 
are our lives compared with their existences! Aged 
to the degree of centuries upon centuries, and yet 
youthful with undiminished lustre, they speak to the 
ear attuned to catch their voice the lesson of eternity. 
More vividly than any other spectacle in nature, 
they serve to symbolize the truth of God's eternity, 
without beginning or end, the same yesterday, today 
and forever. 

SCIENCE OF THE STARS. 

Their Scientific Study. To turn from such contem- 
plation to analysis, seems like breaking a spell or like 
descending from the heights. It is as it were deserting 



102 The Stars. 

poetry for prose, to abandon the first intuitive spirit 
of awe which the nocturnal heavens create and to 
begin to measure with cornpass and rule the distances 
and magnitudes of the stars. 

But, rightly executed, the change needs involve no 
descent. In place of lessening our sense of mystery 
and awe, the study has power to deepen it. For a 
fuller knowledge of celestial measurements will inform 
us of the immensity of space and the colossal scale on 
which the world has been constructed. 

Star Distances. How far from us are those gleam- 
ing lights? They seem our near neighbors, no more 
distant than the clouds. It is our sky they ornament, 
the firmament whose distance seems measurable in 
hundreds of yards rather than in miles. This firma- 
ment is the vaulted ceiling of a great natural hall, 
whose floor is the earth's level with its limiting 
horizon, and in which there seems established a 
perfect proportion of height and breadth. 

But were the stars only a few hundred yards away, 
they would drop to the earth by sheer force of gravity. 
They are far enough off at least to escape the visible 
effect of this attracting force. They are farther from 
us than moon and sun and planets. For these pass 
in front of them at times and shut them from view. 
Like distant lights at sea the stars remain motionless 
while the nearer beacons, sun, moon, and planets, 
move in and out among them. And yet these 
nearer beacons are themselves millions of miles 
away. 

So far beyond lie the stars that our largest telescopes 
leave them unmagnified. Twenty-five trillions of 
miles, such has been calculated to be the distance of 



The Stars. 103 

the nearest of the stars. By such unimaginable and 
almost incredible spaces are the stellar bodies sep- 
arated. 

Star Sizes. If we ask further of what magnitude 
are the stars, again we find that our senses or the 
inferences we draw therefrom deceive us utterly. 
The stars appear as so many electric lamps or even 
candle-lights, almost without dimension or extension. 
But were they no more, they could not have continued 
to blaze throughout the long ages of history. Long 
ago they would have burned to cinders, as do now 
the meteors or shooting-stars. And were they only 
such, they would not be viewable at all at their 
enormous distances. Light spreads as it goes, be- 
coming ever weaker and fainter, till finally it dis- 
appears from sight. The amount of luminosity the 
stars still bring from their prohibitive distances tells 
the story of their unsuspected magnitude. 

It is a certain fact that could the sun be removed to 
the distance of twenty-five trillions of miles, its lumi- 
nosity would be so diminished that it would shine only 
as an ordinary star. The stars are suns, therefore, 
paralleling our solar orb in their immensity. 

Star Magnitudes. By magnitude astronomers mean , 
not the volume of the stars, but their degree of bril- 
liancy. The division of stars into classes according to 
magnitude is, of course, more or less arbitrary. Only 
twenty stars are rated of the first magnitude, ranging 
from Sirius the Dog-Star to Deneb in the Northern 
Cross. A dozen more of these bright orbs are visible 
in ournorthern latitudes, viz. : Capella, Arc turns, Vega, 
Rigel, Procyon, Betelgeux, Altair, Aldebaran, Fomal- 
haut, Antares, Pollux, Regulus, and Spica. 



104 The Stars. 

In the next class, the second magnitude stars, about 
sixty-five are placed. The number goes on increasing 
thus in fairly regular proportion till the sixth magni- 
tude is reached, represented by some five thousand 
stars just at the limit of unaided vision. With the 
telescope much fainter objects can be made out, down 
to at least the fourteenth magnitude. 

Number of the Stars. Again, we may be curious to 
know how numerous are the stars. The naked eye 
counts them by thousands, the telescope by millions. 
Recently the Abbe Moreux gave their number as 
150,000,000. The estimate may be exaggerated, but it 
seems quite Hkely that when the international work of 
cataloguing the stars has been completed, a work 
in which the Papal Observatory at Rome with seven- 
teen others is now engaged, the number will easily 
total 50,000,000. What an enormous army, not far 
below the total citizenship of these United States! 
And every individual of this host is a sun, a fiery world, 
a giant orb as we terrestrials measure size. 

Relation With the Earth. Yet all these legions of 
independent worlds are somehow brought into re- 
lation with our diminutive earth. Whatever they 
be intrinsically and whatever their other purposes 
in the design of God, one purpose we know them to 
have, to relieve the emptiness and darkness of our 
firmament by studding it with innumerable gems of 
sparkling light. Worlds in themselves, they become 
so reduced in size by optical laws that they are trans- 
formed into jewels for the enrichment of our heavens. 
Covering heaven's canopy with pictures outlined in 
light, they engage and gratify our sense of the beauti- 
ful. 



The Stars. 105 

How well-nigh incomprehensible it is that those 
mighty stellar worlds should minister to our delight by 
supplementing the attractions of our petty earth! 
And yet it is right and just. For our faculties and 
qualities are all but infinitely superior to theirs. 
Their grandeur is merely material, ours is spiritual. 
The distances and magnitudes and numbers of the stars 
bow before the powers of him who can measure their 
courses, enjoy their splendor, and contemplate with 
understanding and admiration their wonderful design. 
If the stars symbolize God's eternal serenity, we have 
that within us which typifies the higher attributes 
of God's being. His divine powers of wisdom and 
knowledge and love. 

MORE INTIMATE STUDY. 

To learn anything in detail of objects as distant 
as the stars, would seem altogether beyond the 
bounds of reasonable expectation. A separation of 
trillions of miles without the possibility of nearer 
approach, must bring discouragement, one would 
think, to even the most ardent observer. Science, 
however, seems ignorant of the very word discour- 
agement; and it has dared to face the apparently 
impossible task of exploring the farthest realms of 
space and penetrating their mystery. 

Composition of the Stars. Until fifty years ago, 
it seemed impossible that we should ever learn aught 
of the internal make-up of the stars. But in that 
year was found a key to their composition in the 
establishment of the science of spectrum analysis. 
By the spectrum, as had been known from New- 



106 The Stars. 

ton's time, was meant the band of color into which 
light spreads out when passed through a transpar- 
ent prism. It was now found that the spectrum 
varies according to the source of light, each of the 
chemical elements, as hydrogen, sodium, iron, and 
the rest, giving its own distinctive spectrum when 
rendered incandescent. 

Here, then, was a means for sounding the nature 
of the stars, by analyzing the light they emit. Father 
Secchi, the celebrated Jesuit astronomer, was the 
first to apply the test in 1863, subjecting to it as 
many as four thousand stars, or more than half of 
all that are visible to the naked eye. He arranged 
them in four classes, according to their predominant 
colors and distinctive spectra. Bluish-white stars, 
as Sirius, were found to be rich in hydrogen. Yel- 
low stars, as Capella and our Sun, possessed sodium 
in large quantities. Red stars as Antares, and 
ruby stars of fainter lustre, contained other com- 
ponents. 

One interesting fruit of this study has been to 
learn that in those exceedingly remote worlds there 
are no elements other than what the earth contains. 
In the stars, however, the elements are not com- 
pounded as on the earth into water, granite, and 
the like, but are kept by the extreme heat of fu- 
sion in their original state of chemical simplicity. 
In complexity and variety and adornment, the stars, 
notwithstanding their splendor, are far inferior to 
the earth. 

Temporary Stars. The most peculiar and re- 
markable of all stellar phenomena is the sudden flash- 
ing forth of a star in a part of the sky where none had 



The Stars. 107 

appeared before. The strangeness of such a spec- 
tacle will be the better appreciated if we recall the 
vastness of size attributed to the stars. That a body 
of the proportions of the sun should appear in space 
suddenly and without warning and take its place 
for a few weeks or months in sorne fixed constellation 
and then fade gradually into invisibility, is certainly 
remarkable. 

But the fact has been observed so often that it 
cannot be gainsaid. It was the sudden appearance 
of such an orb of fire in the sixteenth century that 
excited the attention of Tycho Brahe and started 
him on his life-work as an astronomer. Since then, 
fifteen others have appeared at different periods, 
an average of five for each century. The latest 
was the New Star in Perseus, which appearing early 
in the year 1901 and mounting to the first magnitude, 
changed temporarily the map of the constellation. 

Proffered Explanations. No explanation of this 
startling phenomenon can be regarded as altogether 
satisfactory. It has been supposed by some that 
the outbreak of light is due to the impact of one 
great globe on another with the accompanying de- 
velopment of enormous heat. This collision hy- 
pothesis seems to be at the basis of Mr. Percival 
Lowell's recent suggestion, that the earth will one 
day meet its end by colliding with some foreign 
body. 

A more likely explanation is that of a sudden 
tremendous explosion within the body of the star 
itself, accompanied by the release of subterranean 
fires and by other volcanic phenomena, continuing 
for several weeks or months and then slowly sub- 



108 The Stars. 

siding. This would seem to account more satisfac- 
torily for the unexpected blazing forth of the New 
Stars. The occurrence, however, is so distant from 
us and withal so relatively infrequent that we can 
only speculate about its cause. 

Variable Stars. Finally, there is an interesting 
class of stars, composed of those whose light waxes 
and wanes according to a periodic law. The first 
of them was noted by Fabricius at the end of the 
sixteenth century, and was given the appropriate 
designation of Mira or Wonderful. It changes regu- 
larly from the eighth to the second magnitude, in 
a period of eleven months. All that thus alter in 
brightness, albeit in unequal periods, are called 
Variable Stars. 

A large number of these are now known to exist, 
thousands rather than hundreds. Not all of them 
are to be similarly explained. But the variability 
of many is almost certainly due to the interposition 
of a dark planet attendant on the star, crossing it 
at regular intervals and partially intercepting its 
light. The variable stars thus afford fair evidence 
that other stars besides our sun are accompanied by 
planets. 

Recently Campbell of the Lick Observatory in 
California has secured spectroscopic evidence, also, 
of the presence of planets in some of the stellar sys- 
tems, notably in the case of variable stars. Indeed, 
he has announced that there is positive reason to 
believe that one star out of every thirteen in the 
universe is accompanied by one or more planets. 
The sun, then, is far from being the only star 
attended by a planetary system. 



The Stars. 109 

Order of the Universe. Such are the main facts 
gleaned from a close and rigid scrutiny of the stars. 
Passed in review, they teach us that these mighty 
worlds are not scattered promiscuously through the 
universe but well and adequately spaced. Where 
crowding seems to occur, as in the Milky Way, it is 
merely the result of optical illusion. Astronomy 
further depicts them to us, not as flying wildly 
through space and thus endangering the existence 
of their companions, but kept apart and governed 
by some common law which reduces all their move- 
ments to harmony. 

Of imiform structure are all these myriad spheres 
and of similar though not identical composition. Yet 
each is in its own way active, some guiding planets 
on their courses, some blazing betimes with un- 
wonted light, but the vast majority flaming steadily 
and unceasingly, and remaining, therefore, constantly 
visible from our post of observation. Though all is 
not yet revealed, we know enough to affirm that in 
the sidereal world there prevail order and unity no 
less truly than in our own solar system. 



CHAPTER XL 
HABITABILITY OF REMOTE PLANETS. 

Probably the most interesting fact taught by sidereal 
astrononay is that besides the familiar planets of the 
solar system there exist in all likelihood numerous 
other planets, attendant on the several suns of 
nature, the fixed stars. The discovery of these new 
systems of ancillary bodies, may raise again in the 
minds of some the problem of the habitability of 
other worlds than ours. Curiosity respecting the 
possible intelligent occupants of other worlds is not 
to be allayed, we are well aware, by the brief ex- 
position of adverse arguments presented in our earlier 
articles. Like Ban quo 's ghost, speculation on these 
matters will not down. It is bound to rise again. 

New Field for Speculation. An advocate of habi- 
tability may not unjustly make the point that the 
more remote planets recently brought to light offer 
new groimd for speculation. The arguments thus 
far presented, they will contend, by omitting the newly 
discovered planets, leave untouched a whole array of 
celestial bodies whose case is certainly worth con- 
sidering. He, therefore, will petition that the case 
be reopened. 

A pleader of this sort will not rest satisfied with the 
r61e in nature which we have presumed to accord to 

110 



Remote Planets. Ill 

the fixed stars. To constitute a celestial panorama 
for the delectation of us terrestrials, will impress him 
as an insufficient and imworthy destiny for this 
multitude of gigantic bodies. To toss off their pur- 
pose thus lightly, to assign them an office so mean and 
lowly, will appear to this advocate too great a depre- 
ciation of their rank and order. 

A Possible Purpose. In the design of the Creator, 
he may urge, those massive fiery globes which we 
designate as stars, must have some nobler end than 
merely to form for us a celestial picture, and light up 
so dimly our earth on moonless nights. Have we not 
a key to that further and higher purpose in the 
demonstration of the planets by which they are 
accompanied? 

Over these dependent bodies the stars will exercise 
an influence akin to that with which the s\m sways the 
earth. Around each star planets will revolve in 
orderly orbits obedient to its gravitational impulse. 
Of this sort of control neither we nor the habitationists 
can possibly have doubt. Nor can we doubt that the 
stellar planets will be both illumined and heated by 
the radiant energy of the fire of the stars. Like our 
sun, the stars may rightly be assumed to play the 
part of light-giving and heat-supplying centres. 

The Argument for Life. Why, then, may not the 
analogy be pursued, and the stars be construed 
as life-giving centres as well? If in so many regards 
their office is kindred to the sun's, why deny to them 
the further power of vivifying their planets literally, 
by maintaining and fostering therein forms of life 
such as our earth exhibits in such plentiful measure ? 
Are not all the required conditions verified? Given 



112 Remote Planets. 

stable planets capable of affording a firm foothold for 
life and a nearby sun prolific of life-sustaining 
influence, is it not probable that life will arise and 
through the natural process of evolution mount on 
its upward course till there appear on these planets 
beings of as high a type as man? 

The enthusiast for habitability will press the point 
by urging that he thus finds for the stars an adequate 
reason for existence, namely to promote life in the 
systems which they govern. And moreover he will 
plead very forcibly the extreme unlikelihood that our 
earth has been specially selected from so many 
million globes to be the sole and exclusive habitat 
of living beings. 

Persuasiveness of the Argument. That this reason- 
ing has some color of truth, is scarcely to be denied, 
and is indeed attested by facts. For it has secured a 
multitude of adherents, and multitudes do not follow 
error wantonly. The most important of the recent 
converts to the habitation theory is Simon Newcomb 
of Washington, the Nestor of American astronomers. 
His conversion at the eleventh hour is an affair of 
more than passing moment. 

Comparison of this scientist's earlier and later 
pronouncements reveals a change of front respecting 
our present problem of the most remarkable kind. 
Many a passage could be quoted to show that the 
earlier Newcomb viewed with the most absolute 
scepticism all claims for the habitability of other 
worlds. But in Harper's Monthly for August, 1905, 
he appeared for the first time as an advocate, cautious 
if you will, but still a sympathetic exponent of the 
habitation theory. 



Remote Planets. 113 

A Remarkable Conversion. If his change of at- 
titude is already remarkable, the sweeping character 
of his later conclusions is little short of amazing. 
He had just previously labelled the habitation of 
Mars "a pure supposition," and had confessed frankly 
to his perhaps disappointed readers that he knew 
no more of the possible inhabitants of Mars than 
they did, which was "nothing at all." But now 
there came to him a new light. And in the article 
of the year 1905, he no longer excluded "the proba- 
bility that a vast number of worlds might be fitted 
for habitation." "All the analogies of nature lead 
us to believe" that if fitted they will be inhabited. 
"It is therefore perfectly reasonable to suppose that 
beings not only animated but endowed with reason 
inhabit countless worlds in space." 

The present writer can hardly comprehend so 
astounding a reversal of thought. But it has un- 
doubtedly been inspired in part by our newly ac- 
quired knowledge of planets, whose existence was 
not before suspected. And for its argumentative 
basis it must rest on some such line of reasoning 
as has been unfolded in the early part of this paper. 
To this argument, therefore, we should now give 
some attention. 

Value of the Argument. Epitomized, the argu- 
ment says that we must find if possible a worthy 
motive for the existence of the stars. A probable 
motive is that they are to serve their planets by 
fostering life therein. And thus are we saved 
the unnatural hypothesis of supposing the earth the 
only inhabited body in all space. To deny all force 
to this contention would be unreasonable as well as 



114 Remote Planets. 

disrespectful to the men of quality who have urged 
it. But the degree of its force may be questioned 
without the danger of such unpleasant consequences. 

An obvious restriction on its value is that it is 
almost entirely speculative. It cannot be made to 
meet empirical tests. The newly-discovered planets 
are so extremely distant that we can have no hope 
either now or in the future of bringing them within 
the range of observational investigation. Neither 
the advocates nor the opponents of habitability can 
entertain the hope of obtaining a shred of positive 
pertinent evidence. And in a matter of this sort 
the burden of proof would seem to rest on those who 
take the positive side. 

Worth of Speculation. It is not to be forgotten 
that in the past similar speculations have been in- 
dulged in, which are now completely discredited and 
relinquished. As before noted in these essays, the 
best of astronomers once thought that the sun and 
the stars were fit for habitation and therefore proba- 
bly inhabited. The grounds of their belief were 
essentially no other than those at present alleged, 
a worthy purpose for these bodies and the reduction 
of the earth to its proper rank as a relatively insig- 
nificant part of the universe. 

But when the day came that they were driven from 
this position by incontrovertible facts, these men 
or their successors, in perfectly good faith and guided 
by probability, transferred their speculations to 
the planets of the solar system. But even from this 
ground they were soon forced to retreat. Within 
the solar system their only present refuge lies in the 
planet Mars. 



Remote Planets. 115 

Weighing of Probabilities. The fate of these spec- 
ulations of the past should teach us caution. But 
perhaps the present speculations, as those of New- 
comb, have been more cautiously framed. In the 
study of nature we have often to depend on prob- 
abilities. And in mooted questions, wherein cer- 
tainty is unattainable, it is the part of the prudent 
scholar to lean to the more probable side. The 
probability, however, must be genuine to justify 
his even qualified assent. 

Is there this sort of probability for the claim that 
the remotest planets are inhabited? The claim 
rests on two grounds, that the stars being suns have 
power to sustain life, and that the earth cannot be 
alone in its possession of life. 

The first reasoning is perceptibly weakened by the 
consideration developed in an earlier chapter that 
the sustenance of life is quite a different process 
from the first creation of life and is in comparison a 
power of infinitely inferior kind. The life-sustaining 
properties of the stars, therefore, can prove nothing 
for the habitation of their dependent bodies. 

Singularity of the Earth. That the earth is alone 
inhabited, does seem at first unlikely. But nature 
is full of mysteries and this may be one of them. It 
seemed unlikely once that the other solar planets 
from Mercury to Neptune should remain unblessed 
with living inhabitants. But in their case, with one 
possible exception, the unlikely has now been found 
to be the true. What reason have we for supposing 
anything different for the stellar planets? New- 
comb speaks of the analogies of nature. If analogy 
teaches anything in this matter, it is that uninhab- 



116 Remote Planets. 

ited globes are the rule, and an inhabited globe the 
rarest of exceptions. 

It is the earth's singular conditions and not the 
mere fact of its being a planet, that adapt it so well 
to be the residence of life. It lies in the temperate 
zone of the solar system. Its nutrient materials, 
its varied topography, its changes from season to 
season, and even from day to night, all these special 
conditions favor the reposeful continuance of life and 
its countless species. Are there any other planets 
in all nature where the same happy conditions are 
realized? Who shall affirm this to be true or even 
probable ? 

The Criticism Applied. How extreme in the light 
of these considerations must now appear the state- 
ment of a grave astronomer, that "it is perfectly 
reasonable to suppose that beings not only animated 
but endowed with reason inhabit countless worlds 
in space"! Has not our grave astronomer been 
nodding? And may we not appeal from Newcomb 
dormitans to Newcomb vigilans? We venture the 
appeal and quote his earlier phrases which we beg 
even now to make our own, that the habitability 
of other worlds is "a pure supposition," and that 
"the only reason to believe in such inhabitants is the 
fact that our earth is inhabited." 



CHAPTER XII. 
THE BIBLE AND ASTRONOMY. 

To the Catholic versed in astronomy there could 
scarcely be proposed a more inviting subject of in- 
quiry than the relations between that science and the 
Holy Bible. Years of delightful study, on the one 
hand, have bred in him a genuine love for the science 
of the heavens. Years of religious habit, on the 
other, have taught him to cherish the Holy Book, 
as the ultimate fount of revealed truth. To search 
the Scriptures, then, for points of contact and, if 
it so chance, signs of agreement between the two 
revelations, the natural and the divine, will appeal 
to him as perhaps could no other task. 

Two Recent Guides. To aid in this important 
study, there are fortunately at hand two excellent 
books of recent date dealing expressly with the 
astronomical references of the Bible. Schiaparelli, 
the discoverer of the Martian canals and the most 
renowned of recent Italian astronomers, has lately 
contributed to the literature of the subject a valu- 
able work entitled "Astronomy in the Old Testa- 
ment." And in 1908 there was issued a volume of 
somewhat wider scope, called "The Astronomy of 
the Bible," by Mr. E. W. Maunder, Fellow of the 
Royal Astronomical Society. The appearance of 

117 



118 Bible and Astronomy. 

such works from the pens of expert scientists is it- 
self a tribute to the interest of our subject. 

One can be sure of safe and reliable guidance in 
following either of these publications. They ema- 
nate from authorities at once competent and im- 
partial, this twofold quality not being impaired by 
the additional grace of a becoming reverence for the 
Sacred Scriptures. We feel secure, therefore, in 
adopting them as our chief guides in the summary 
we now propose to give of the astronomical teach- 
ings of the Bible. 

Teachings Respecting the Earth. Foremost among 
the principles of modem astronomical science is the 
now familiar truth that the earth is a body of spheri- 
cal shape suspended in space. It would be unnatu- 
ral to expect that the Hebrews could in their early 
period have become acquainted with this geographi- 
cal fact. But it is interesting to learn that the 
Scriptures suggest no contradiction of the fact and 
even contain allusions quite in keeping with it. 

There are several texts indicating that the ancient 
Hebrews viewed the earth as a mass set apart, limit- 
ed in extent and surrounded on all sides by empty 
space. The Book of Ecclesiastes, for example, in 
its first chapter speaks of the sim as "rising and go- 
ing down and returning to his place," words which 
clearly signify a complete daily circuit of the sun 
about the earth. 

To the moon, also, according to Schiaparelli, a simi- 
lar course was probably attributed. And in Judges, 
V, 20, there is a reference to the orbits of the stars. 
With this correct concept of an enclosed and limited 
earth, contrast the contemporary teaching of Xeno- 



Bible and Astronomy. 119 

phanes, the Greek philosopher, who supposed that 
the earth was infinite in extent and as a consequence 
that each day's sun and moon and stars were new 
creations. 

Here may be recalled also the remarkable passage 
in Job, xxvi, 7, where it is said that the Lord "stretch- 
eth the north over the empty place and hangeth the 
earth upon nothing." We need not go so far as did 
Lord Bacon who discovered here a reference to the 
roundness of the earth. But there is certainly here 
the absolutely correct teaching that the earth re- 
mains hung in space without support. How this 
rises above the grotesque fancy of the ancient Hin- 
dus, who thought the earth supported by an elephant, 
the elephant by a tortoise, and the tortoise by a snake! 

Character of the Heavens. The heavens above the 
earth, naturally our next object of interest, present 
to the glance the aspect of a solid blue vault or arch. 
But we know to-day that this appearance is merely 
an effect of optical illusion. For beyond the atmos- 
phere there is for the most part only wide-stretch- 
ing space. Some have imputed it as a fault to the 
Hebrews and as a sign of their ignorance in matters 
scientific, that in their Scriptures they often refer 
to the skies by the name firmament, a word betok- 
ening utmost firmness and solidity. 

But it is interesting to learn that, in the opinion of 
at least a fair number of critical scholars, the He- 
brews themselves never employed a word answer- 
ing to our "firmament," and are, therefore, saved 
the dishonor, if such it be, of having conceived the 
sky as a rigidly solid vault. Before reaching us, the 
Hebrew Scriptures have passed through the hands 



120 Bible and Astronomy. 

of Greek translators of the third century before 
Christ. These translators, consonantly with the 
Greek astronomy of the time, rendered the Hebrew- 
names for heaven by firmament. The error of sup- 
posing the heavens solid as crystal was certainly 
an element in the ancient Greek philosophy. It is 
extremely doubtful if it formed a part of the natural 
philosophy of the Inspired Books. 

Hebrew Names for Heaven. The Hebrews in their 
prose writings used two words for heaven, one meaning 
* 'expansion" and the other ' ' uplifted. ' ' These are the 
designations which the Greeks mistranslated into 
firmament. Either of them would be accepted even 
in our day of scientific progress as fitting and appro- 
priate. For the heavens are to all appearances 
stretched out from zenith to horizon and uplifted 
high above the earth. 

In their poetical writings, indeed, the sacred writers 
often pictured the skv as a tapestry or curtain, or 
again as a pavilion or tent, as in Isaias xl, 22, **He 
spreadeth out the heavens as a tent to dwell in." 
But such terms are plainly figurative, and in keeping 
with the poetical character of the chapters in which 
they occur. Interpreted as metaphors, they allow 
us still to believe that the Hebrews thought of the 
heavens much as we do today, not as a solid vault, 
but as an empty space spread out above the earth 
and lifted up on high. 

The "Windows of Heaven." Some scientific purists 
have taken offence at the expression, windows or 
floodgates of heaven, occurring a half a dozen times 
in the Old Testament books. Mr. Andrew D. White 
cites the phrase as one example among several of the 



Bible and Astronomy. 121 

gross ignorance of the Hebrews respecting natural 
phenomena. But is it true that the Hebrews actually 
believed in windows or sluices in the sky which served 
as sources of the rainfall? 

Schiaparelli, indeed, accepts the expression as 
literal. But even with this great master we may 
feel compelled at times to part company. And our 
other authority, Maunder, argues certainly with some 
show of reason that the "windows of heaven" was a 
purely figurative expression, since there is no sign in 
the sky that would have suggested even to simple 
minds windows or floodgates in the literal sense. 

Source of the Rain. A literal interpretation of this 
passage supposes furthermore that the Hebrews 
believed in a great reservoir of water above the 
firmament whose streams would be let down through 
windows from time to time in the form of rain. But 
it was certainly known to many of the inspired writers 
that rain came from the clouds. To this effect could 
be quoted Ecclesiastes xi, 3, Judges v, 4, Genesis ii, 
6, and perhaps the Second Book of Kings, xxii, 11. 

The gifted author of the Book of Job described 
correctly the manner in which the clouds are formed. 
"He lifteth up the drops of rain and poureth out 
showers like floods ; which flow from the clouds that 
cover all above." Job xxxvi, 27-28. With this 
knowledge that the clouds are the real sources of the 
rain, a belief in literal sky-windows or floodgates would 
seem to be inconsistent. We prefer, therefore, to 
hold to the milder view that explains the windows 
of heaven as one example among many of the bold 
and daring but finely poetic images used by the in- 
spired writers. 



122 Bible and Astronomy. 

Waters Above the Firmament. Finally, everyone 
will remember how in the account of the creation God 
is represented as having on the second day * 'divided 
the waters that were under the firmament from those 
that were above the firmament." Two or three 
times later in the Bible reference is again made to 
"the waters that are above the heavens. ' ' This phrase, 
if taken as it stands, would seem to involve a scientific 
misconception. 

But if the firmament or heaven be understood 
simply of the atmosphere, then the water of the clouds 
may not improperly be said to be above the firmament 
as resting thereon, and the Scriptural phrase is 
acquitted of all charge of falsity. There is reason to 
believe that this was the sense intended. For "the 
Hebrews supposed three heavens," so the Century 
Dictionary declares, "the air, the starr}^ firmament, 
and the abode of God." Is it not likely that the 
author of Genesis had in mind the first and lowest of 
these heavens, the atmosphere, whereby the waters 
of the clouds above are truly divided from the waters 
of the earth? 

Science of the Bible. From the preceding summary 
it must appear that the sacred writings are innocent 
of many of the so-called scientific puerilities which 
it is the fashion in some quarters to impute to them. 
In compositions so ancient, limitations of scientific 
knowledge are to be expected. But in the field 
covered thus far, there appears in the Bible no clear 
indisputable case of scientific error. 

On the contrary, there are in the Sacred Books the 
correct teachings of an earth suspended in space, of 
an expanse spread above the earth, and of the clouds 



Bible and Astronomy. 123 

as true sources of the rain, lifted above the atmosphere 
and by it sustained. And more important still in 
the degree that philosophy is superior to science, 
there is the true philosophical teaching of a God 
who "upholdeth all things by the word of His 
power." Hebrews i, 3. 



THE HEAVENLY BODIES. 

Ideal of Wisdom. In the Book of Wisdom it is 
told of Solomon that he knew the constitution of the 
world, the changes of seasons, the revolutions of the 
year, and the dispositions of the stars. In these 
phrases was summed up, we may suppose, the Hebrew 
ideal of astronomic wisdom. How far this ideal was 
realized in practice, we have already partly told in 
our explanation of the views of this people regarding 
the earth and the heavens. We have now to recount 
some particulars of their knowledge of the celestial 
bodies, the objects with which the firmament is 
emblazoned. 

General Teachings. In the first chapter of Genesis 
occurs a classification of the heavenly bodies, whose 
extreme simplicity bears witness to the antiquity of 
its composition. "God made tw^o great lights, a 
greater to rule the day, and a lesser to rule the 
night, and the stars." Later the psalmist re- 
peated the same enumeration in slightly altered 
form: "God made the great lights, the sim to rule 
the day; the moon and the stars to rule the night." 
And as if to declare the purpose of their being, both 
psalmist and prophet bade these objects give glory 
to the Creator. "Praise the Lord, O sim and moon; 



124 Bible and Astronomy. 

praise him, all ye stars and light." "O ye sun and 
moon, bless the Lord; ye stars of heaven, bless the 
Lord. ' ' 

In all these passages we have the same collocation 
of the bodies of the firmament. It is, to be sure, a 
grouping of the very simplest sort. But it represents a 
first natural and not imworthy attempt to place the 
lights of heaven properly in the order of that rank. 

Teachings Respecting the Sun. As of the highest 
rank among the celestial lights, the sun is naturally 
the oftenest mentioned in the Scriptures. While 
most of the references are of too common a sort to 
repay recital here, a few stand out by reason of some 
particular significance. 

Perhaps finest of all is the poetical description in the 
eighteenth psalm, where the orb of day is likened, 
now to a bridegroom emerging from the nuptial 
chamber, now to a hero rejoicing to run his way. 
Bridegroom and hero, "his going out is from the end 
of heaven and his circuit even to the end thereof; and 
there is no one that can hide himself from his heat." 
Besides being thus properly conceived as our chief 
source of light and heat, the sun was also noted in 
Deuteronomy, xxxiii, 14, as one among the sources of 
the fruits of the earth. With these attributions may 
be compared our own earlier description of the sun 
as the earth's principal source of light and heat and of 
the sustenance of life. 

Sunrise and Sunset. To the Catholic one of the 
most familiar of Scriptural refrains is that which 
reads, "From the rising of the sun to the going down 
of the same." The rhythm of the phrase has com- 
mended it to Catholic and Protestant translator alike. 



Bible and Astronomy. 125 

and there is no one that fails to appreciate its literary 
propriety as expressive of the fulness of the day's 
length. 

There may be critics captious enough to take ex- 
ception to the phrase on account of its technical 
inaccuracy. For science has now discovered that the 
phenomena in question are due to the earth's motion 
and not the sun's. And the critic may argue that in 
this particular the Scriptures have been guilty of an 
error of science. But to this criticism the answer 
may fairly be made that there is truth in phenomena 
and appearances as well as in ultimate realities. 
That the sun rises and sets, is not altogether false and 
has never been so adjudged. 

Even today, when the truth is more completely 
known, we do not hesitate to speak and write of 
sunrise and sunset, even in our almanacs, prepared by 
scientific hands. What critic so captious as to con- 
demn these usages because of their technical inaccu- 
racy? And in the face of this example of present 
practice, what need is there of subtle argumentation 
to defend the Sacred Books from the charge of scien- 
tific falsehood? 

There would have been guilt of error, it seems to us, 
only in the circumstance that the Scriptural writers, 
having the question distinctly before their minds, had 
asserted professedly that the sun revolves and not the 
earth. Since no such positive teaching was intended 
or included, the charge of error falls. The truth that 
resides in natural phenomena is justification by 
itself for the Hebraic formula, "From the rising of 
the sun to the going down of the same, the name of 
the Lord is worthy of praise." 



126 Bible and Astronomy. 

The Moon and the Calendar. In the ordering of the 
national life of the Jewish people, the moon was an 
even more important factor than the sun. On the 
succession of its phases was based the month, for 
them a more significant division of time than the year. 
At the time of our Lord and probably during many 
centuries earlier, it was the custom for observers 
especially appointed for the purpose to watch for the 
first appearance of the young crescent moon in the 
west. Its appearance signalled "the new moon," a day 
to be observed with religious ceremonies, the sounding 
of trumpets and the offering of sacrifices. From the 
beginnings of the Mosaic ritual down to the present, 
"the new moons" have been kept as holy days by the 
Jews. 

Their two chief festivals, of the Passover and of 
Tabernacles, were also determined from the phases of 
the moon. The Passover began on the fourteenth 
day of the first month, at the time when the first 
moon of the vernal season was at its highest phase. 
And six months later came the joyous feast of Taber- 
nacles, beginning also like the Pasch at the full of the 
moon and like it prolonged for an entire week. A 
third great feast of only one day's duration was 
celebrated seven weeks after the Pasch. By bringing 
the Apostles to Jerusalem, this last became the occasion 
of our Christian festival of Pentecost. And from the 
Passover has been derived the date of the Christian 
Pasch or Easter, which is also determined by law from 
the full moon of the first month of the tropical year. 

"God had appointed the moon for seasons," so the 
Psalmist announced, and the author of Ecclesiasticus 
added, "From the moon is the sign of the feast day." 



Bible and Astronomy. 127 

When we remember to what extent the Israelites, liv- 
ing in the fields and not in towns, were dependent for 
many practical conveniences on the shining of the 
moon, we shall understand how it came to play so 
all-important a part in shaping their civil and religious 
calendar. Their month unlike ours was literal, 
starting at the first appearance of the crescent moon. 
And their most glorious festivals were made to coin- 
cide with days on which the moon was in its most 
resplendent phase. 

The Stellar World. To the lesser lights of heaven, 
the stars, the Scriptures make many general references 
that are not uninteresting. "The orbits of the stars" 
is an allusion of special interest because of its occur- 
rence in Judges, one of the earliest of their books. 
It was another ancient chronicler who called ad- 
miring attention to the number of the stars. "Look 
up to heaven and number the stars if thou canst." 
Genesis, xv, 5. Already they appreciated the distance 
of the stars as too great for measurement. "Who 
hath measured the height of heaven, the breadth of 
the earth and the depth of the abyss ? ' ' Ecclesiasticus , 
i, 2. From these and similar references we gather 
that the Sacred Writers were not inattentive to the 
grander phenomena of the sidereal world. 

In addition, some of the more important star- 
groups had been singled out for special mention. 
Not only in Job but also in Amos, Isaias and the 
Fourth of Kings, we find a specification of certain 
definite constellations. Though translation is often 
difficult, it is agreed on by nearly all authorities that 
there is distinct and repeated reference in the Scriptures 
to the star-groups now called the Pleiades, Orion, and 



128 Bible and Astronomy. 

the Great Bear. Even the amateur in astronomy 
needs not be informed that these three are the most 
conspicuous and spectacular of the constellations. 

Two or three other groups were designated also, but 
on their correct interpretation opinion is divided, and 
choice must be made among the Signs of the Zodiac, 
the Hyades, the Lesser Bear, and some others. The 
problem of their identification is, according to Miss 
Gierke, among the most perplexing. 

An Array of Texts. To the astronomer it is instruc- 
tive to compile the texts that contain clear mention 
of individual constellations. For completeness we 
append them here in the translation that seems most 
approved by recent scholars. 

Job, ix, 9: "He maketh the Great Bear, Orion, the 
Pleiades, and the chambers of the south." 

Job, xxxviii, 31-33 : "Shalt thou be able to join the 
shining stars the Pleiades or loose the bands of Orion? 
Canst thou bring forth Mazzaroth (?) in his season, 
or canst thou guide the Great Bear with his sons?" 

Amos, V, 8: "Seek Him that maketh the Pleiades 
and Orion." 

Fourth Kings, xxiii, 5: Some "burned incense to 
the sun, the moon, to Mazzaroth (?) and all the host 
of heaven." 

Finally, there is again reference to Orion in Isaias, 
xiii, 10, and to "the chambers of the south," in Job, 
XXX vii, 9. 

A Theocentric Astronomy. We have quoted these 
texts both for their intrinsic interest and also to justify 
the contention that the ancient Hebrews were in no 
mean degree observers of the heavens. Their knowl- 
edge, if crude, is at least worthy to be compared with 



Bible and Astronomy. 129 

that of average men of today. Now it was on such 
knowledge, respectable in amount and kind, that they 
based their conception of the might and wisdom of 
Jehovah to whom their science of astronomy always 
reverted as its centre. "Lift up your eyes on high," 
cried the prophet Isaias (xl, 21), "and see who hath 
created these things, who bringeth out their host by 
numbers and calleth them all by their names. 
By the greatness of His might and strength and 
power not one of them was missing. . . The 
Lord is the everlasting God, Who hath created the 
ends of the earth." 



CHAPTER XIII. 
THE BIBLE AND STAR WORSHIP. 

The history of nearly all the nations of the ancient 
world is stamped and stained with the record of their 
indulgence in superstitious practices. At one time 
their superstition took the form of idolatry, the wor- 
ship of graven images, at another of nature-worship, 
the adoration of purely natural objects ; and in nature 
the favorite objects of worship have been most often 
the sun, the moon, and the stars. 

It might have been expected that the ancient 
Hebrews, who were lovers of nature to an extra- 
ordinary degree, would give themselves over whole- 
sale to the same superstitious practices. Lapses of the 
sort did, indeed, occur, but never to meet with official 
sanction as in the case of the surrounding Gentile 
nations. On the contrary, throughout their history 
as the chosen people of God, their authentic and in- 
spired books never ceased to protest against all such 
idolatries as abominations. 

Earliest Denunciations. The first commandment 
of their Decalogue sounded the keynote for all their 
subsequent ordinances: "I am the Lord thy God; 
thou shalt not have strange gods before Me." By 
this first article of their faith the people of Israel 
were forbidden ever to pay homage of adoration to 
other than the one true God. 

130 



Bible and Star Worship. 131 

Later we find this general cornrnandment partic- 
ularized so as to apply expressly to the worship of the 
heavenly bodies. In the Book of Deuteronomy, 
iv, 19, we come upon a warning against all who would 
"lift up their eyes to heaven, and see there the sun and 
moon and stars, and being deceived by error would 
adore and serve them." That there was need of the 
prohibition is evident from its repetition in a later 
chapter, xvii, 3: "Thou shalt not transgress His 
covenant so as to go and serve strange gods, the sun 
and moon and all the host of heaven." Such was the 
standard set the Jewish people in the beginning by 
the command of God. 

Lapses into Error. From this correct and exalted 
standard the Jewish people fell away, it is true, at 
many a period both early and late in their history. 
If these scandals are duly recorded in the Sacred 
Books, it is never that they may be condoned or 
justified. On the contrary, they were recorded only 
to be deprecated, and every new lapse into error was 
made providentially to serve as an occasion for a 
reiterated promulgation of the Mosaic Law. For 
both early and late in every period of the history, 
prophets and kings lifted up their voices in wrathful 
denunciation of these abominable practices. 

Already in the time of the Judges, and hence before 
the days of Saul and David, the Israelites now en- 
camped in Palestine had learned from the Canaanites 
the false worship of Baal and Astarte. The former 
divinity, the sun-god, was worshipped on the moun- 
tain-tops; while his companion, Astarte, whom 
Maunder believes to have been the goddess of 
the moon, was worshipped in groves called sacred 



132 Bible and Star Worship. 

because dedicated to her. Everyone familiar with 
the sacred text will recall the frequency with which 
both "the high places" and "the groves" are de- 
nounced in Holy Scripture. 

Phenicians and Israelites. It was chiefly from the 
Phenicians, a Canaanite tribe inhabiting the coast, 
that Israel had learned the false lesson of the worship 
of sun and moon. They were the nation to whom 
we now trace traditionally the invention of the writ- 
ten alphabet. And to the Phenicians of Tyre and 
Sidon the world owes also some of its most valuable 
lessons in commercial enterprise. It was adventurous 
merchants of this race that founded in early times the 
province of Carthage, which continued to exist pros- 
perously for almost a thousand years till overwhelmed 
by the superior might of Rome. 

But if their pioneer work in letters and trade is still 
remembered with honor, their religious system has 
long since fallen vinder reproach. When Israel, 
emerging from the wilderness into the Promised Land, 
had achieved its conquest of the major part of 
Palestine, there ensued a conflict between two 
religions, the idolatry of the Phenicians and the 
monotheism of the Jews. How steadfastly the 
Jewish prophets resisted the encroachments of 
Phenician superstition, can be read in many a chapter 
of the Bible. And which of the two finally con- 
quered, is known to all the world. We owe indeed to 
Tyre and Sidon lessons of mental culture and com- 
mercial enterprise, but we owe to Judea, at least 
ultimately, our knowledge of the one true God. 



Bible and Star Worship. 133 

THE ROYAL PERIOD. 

Lapses Under the Kings. Continuing the history, 
we should learn how under Solomon and the later 
rulers of Judea and Israel, the idolatrous practices of 
surrounding peoples were again and again copied by 
the unfaithful Jews. Perhaps the most powerful 
and baneful of these influences came from Babylonia, 
where astronomy had long since degenerated into 
astrology and astrolatry. As Palestine fell more and 
more under the power of the Eastern kingdom, we 
can imagine how the danger grew that its monotheism 
would succumb to the false religion of Babylon. It 
is told in the Fourth Book of Kings, xvii, 16, that in 
the time of Osee, king of Israel, the people "adored 
all the host of heaven and served Baal." But Provi- 
dence intervened and punished those unfaithful 
northern tribes by delivering them into captivity in 
the year 721 B.C. 

Thesouthem kingdom, with Jerusalem as its capital, 
was destined to survive for upwards of a century 
longer. And here it befell, as related in the Fourth 
Book of Kings, xxi, 3, that Manasses, king of Juda, 
set up altars to Baal and adored and served all the 
host of heaven, even to the extreme of bringing their 
worship into the very Temple at Jerusalem. But 
soon there came Josias, one of the wisest and holiest 
of Juda's kings, who cast out and burned all the 
equipment of the worship of Baal and the host of 
heaven. 4 Kings, xxiii. Continuing his work of 
purification, he destroyed those that had burned 
incense to Baal and to the sun and moon, to Mazzaroth 
and all the host of heaven. And he took away the 



134 Bible and Star Worship. 

horses of the sun which unfaithful kings had placed 
in the temple of the Lord. Thus was restored 
again to its former place of honor the true service 
of Jehovah. 

Voices of the Prophets. Would we know the true 
and official teaching of Israel, we must listen to the 
voice of her accredited prophets. At all periods these 
sounded the self-same note. "The prophets of Israel, ' ' 
writes Schiaparelli, "never wearied of threatening 
the most terrible punishments on star- worshippers." 
All who have listened to Mendelssohn's great oratorio 
will remember the vigor of Elijah's contest with the 
prophets of Baal and the issue of the conflict, and 
Elijah was only one of a school whose teaching never 
varied. 

Read, for example, the books of Isaias, Jeremias 
and Ezechiel, the major prophets, and of the minor 
prophets Amos and Sophonias, for testimonies of 
this concurrent teaching. Listen to Isaias, of all the 
most eloquent, protesting against Babylonian en- 
chantments and divinations. "Let now the astrologers 
save thee (if they can) , they that gazed at the stars to 
tell thee the things that might come to thee." Isaias, 
viii, 19; xlii, 12-14. 

Listen to Jeremias on the eve of Juda's downfall 
prophesying that there shall be cast out on the plain 
the bones of all that had loved and served the sun and 
moon and host of heaven, and that all these shall 
remain without burial. Jeremias, viii, 1-2. Read 
Ezechiel, the prophet of the exile, as he denounces all 
idolaters and especially those that stood with backs 
to the door of the Temple facing the east that they 
might adore the rising sun. Ezechiel, viii, 11 ; xvi, 17. 



Bible and Star Worship. 135 

Further Testimonies. If space would allow, many 
other Scriptural passages could be cited to illustrate 
the Bible's constant condemnation of these and 
kindred superstitions. Some texts, as that in 
Sophonias, i, 4-5, would be found so plain as to need 
no commentary. In others the reference would be 
more veiled, as in the case of Amos, v, 26, where, 
however, it is certainly the prophet's intention to 
rebuke the practice of astrolatry. 

Among the most interesting of these more or less 
veiled references are those contained in Jeremias, 
vii, 18, and xliv, 17 sqq. Here the prophet inveighs 
against those who "made cakes to the queen of heaven 
and offered her libations and other sacrifices." The 
whole point of the denunciation is missed unless it is 
noted that by the "queen of heaven" is meant the 
moon. This was the astral body which the Israelites 
were most tempted to adore, since it was from the 
moon's phases, as our last chapter related, that the 
Jews determined their festivals and their calendar. 

Honor of the Hebraic Teaching. How remarkable 
and honorable it was that the Sacred Writers should 
thus have fought so continuously against the idolatries 
that beset the surrounding nations ! Even astrology, 
a lesser sin than astrolatry, received from them no 
countenance. It is probable, indeed, that some 
Hebrews fell victims to a belief in astrological 
practices. But, as Schiaparelli says in a notable 
paragraph worthy to conclude this subject, these 
lapses into astrology "were aberrations of a temporary 
character, and it is no small honor for this nation 
to have seen the inanity of this and all other forms 
of divination. The great prophet of the exile sar- 



136 Bible and Star Worship. 

castically reproaches the Babylonians for having faith 
in the 'dividers' of heaven (that is, the astrologers) ; 
while Jeremias exclaims 'Fear not the signs of heaven, 
at which the heathen are dismayed.' Subsequent 
history shows that these warnings had their effect. 
Of what other ancient civilized nation could as much 
be said ? ' ' 



CHAPTER XIV. 
THE MIRACLE OF JOSUE. 

In the chapters just preceding we have presented 
examples illustrative of the relation between the Bible 
and astronomy. The assembling of these examples 
has served to make manifest that the Israelites were 
far from being devoid of interest in celestial phenom- 
ena. It must also have convinced the candid reader 
that in the cases cited there exists no serious conflict 
or discord between the Jewish teachings and the dis- 
coveries of modem science. There remains now for 
consideration one Biblical incident of peculiar astro- 
nomical interest. 

Stopping of the Sun. The most remarkable narra- 
tion in the Old Testament from the astronomer's point 
of view is that in which Josue, the successor of Moses, 
is said to have stayed the course of the sun. The 
miracle is recorded in verses 12-14 of the tenth chap- 
ter of the Book of Josue. For a proper understanding 
and estimation of the story of the miracle, one ought 
to connect it with its context by reading and weighing 
the earlier verses, also, of the chapter. For the mo- 
ment, however, we will content ourselves with quoting 
only the precise passage in which the miracle is 
recounted. 

"Then Josue said in the presence of Israel: Move 
not, O sun, toward Gabaon, nor thou, O moon, 

137 



138 Miracle of Josue. 

toward the valley of Ajalon," or, according to another 
translation, ** Sun, stand thou still above Gibeon and 
thou, moon, in the valley of Ajalon ! And the sun and 
moon stood still till the people revenged themselves 
of their enemies. Is not this written in the Book of 
the Just? So the sun stood still in the midst of 
heaven, and hasted not to go down the space of one 
day. There was not before or after so long a day, the 
Lord obeying the voice of a man and fighting for 
Israel." 

Popular Interpretation. It has been the custom in 
the past to interpret this passage in an absolutely 
literal sense. Most persons have taken the text at its 
face value, and have accordingly understood the in- 
spired author to say that on the occasion of a certain 
battle both sun and moon were literally stopped in the 
heavens at the command of Josue to allow him time 
to bring the conflict to a successful issue. According 
to this literal interpretation, both of the luminaries in 
question paused in their diurnal journey across the 
sky, causing that day to be actually longer than the 
normal day of twenty-four hours. Indeed the popu- 
lar interpretation has supposed that at the moment of 
the miracle the sun was about to set and the moon had 
just risen and that in these positions both were held 
for the space of an entire day. 

Let it be said at once that the last element in the 
popular interpretation is a pure addition to the Sacred 
Text. Not only is it without warrant to suppose that 
the sun was setting, but the supposition is flatly con- 
tradicted by the geographical situation described in 
the narrative. For Gibeon is east of the valley of 
Ajalon and therefore, according to the very terms of 



Miracle of Josue. 139 

the narrative, the sun was at the time of the miracle 
towards the east, the valley of Ajalon being situate 
towards the west. Observe, moreover, that it is dis- 
dinctly stated that "the sun was stopped in the midst 
of heaven," which could not possibly apply to a posi- 
tion near to the horizon. In the sacred narrative, 
then, there is nothing to convey the impression that 
the sun, about to set, was detained in that position for 
the space of a day. There is clearly question of some 
other portion of the day than the evening hour. 

A True Miracle. There is just as truly question, 
however, of a veritable miracle. The whole narrative 
indicates an incident not only above the ordinary, but 
outside the province of the forces of nature. God 
fought for Israel on that memorable day and lent the 
aid of His almighty power to the battling armies of 
his chosen people. 

The vigorous Scriptural expression that "God 
obeyed the voice of a man" is of course figurative in 
part, since obedience to man cannot be literally pre- 
dicated of the Deity. But while the form of speech 
is hyperbolical, the truth substantially stands that 
at the petition of Josue, the leader of His chosen 
people, God wrought a miracle to bring victory to 
their arms. 

No one who is solicitous for the integrity and in- 
spiration of the Scriptures can permit that the inci- 
dent be interpreted otherwise than as a miraculous 
happening. Reverence alone would forbid us to 
explain the event on purely natural grounds. Here, 
as so often in the Bible, God is pictured as having for 
adequate reasons intervened to alter temporarily the 
ordinary course of nature. Onty the infidel can deny 



140 Miracle of Josue. 

the possibility and even probability of such occasional 
interventions. 

Character of the Miracle. Nevertheless, there may 
still remain question of the precise character of the 
miracle which the sacred writer meant to record. An 
apparent delay of the sun in its course would involve 
so stupendous and far-reaching an alteration of one 
of nature's laws, that astronomers of the utmost rev- 
erence have asked if the Sacred Text is not capable of 
some other well-warranted interpretation. For if the 
text be taken at its face value, we must suppose, not 
indeed that the sun and moon stood still in the sky, 
for their diurnal motion is only apparent, but that the 
earth ceased wholly or in part its movement of rota- 
tion, lost suddenly its swift speed of a thousand miles 
an hour, and remained at rest till the victory should 
have been won. 

That God could have so acted with our relatively 
diminutive earth, no believer can deny. And if one 
cares still to adhere to this literal understanding of 
the text, one cannot be charged with want of brains, 
nor can absolutely convincing evidence be found in 
the sacred narrative to prove this interpretation false. 
However, it can be readily understood why astronom- 
ers, inspired with a love for both science and revela- 
tion, have sought to read more deeply into the mean- 
ing of the Sacred Text. 

MODERN THEORIES. 

The Passage a Quotation. It is not altogether 
without importance to note that the passage at issue 
is a quotation from an earlier narration. No mere 



Miracles of Josue. 141 

theory, but the dictum of the Inspired Book itself, 
informs us of this. For the narrative says plainly, 
"Is not this written in the Book of the Just?" In view 
of this certain fact, Schiaparelli with many others 
throws the responsibility for the relation back on the 
unknown author of the earlier volume. 

This distinguished author points out, moreover, 
that the Book of the Just was a collection of songs 
concerned with the heroic deeds and great men of 
Israel. The poetical character of the work justifies 
us, he thinks, in interpreting the incident freely. And 
he observes rightly that "one could not conceive a 
more effective flight of fancy" than the representation 
of the stopping of the sun by Israel's great commander, 
"or one more fitted for the heights of an heroic and 
lyrical composition. " 

But, interesting as is this suggestion, it does not 
explain with complete satisfaction the fact of the 
incorporation of the incident in our Bible. The 
author of Josue, while borrowing the text, seems to 
have made it his own. He has given it his sanction. 
We might be in danger of questioning too far the truth 
meant to be expressed, if we resorted to the hypothesis 
that the narration is no more than a flight of poetical 
fancy. Poetical to some degree, it must contain 
lodged within it a kernel of truth. 

A New Interpretation. A very recent interpretation 
by Maunder is brimful of interest as at once saving 
the miraculous character of the incident related and 
evading at the same time the astronomical difficulty. 
In a thorough study of the Bible story, some thirty- 
five pages in extent, he attempts to reconstruct the 
exact situation in which the Israelites were placed on 



142 Miracle of Josue. 

that eventful day. From an examination of the 
evidence he concludes that the event probably oc- 
curred in the third week of the month of July, when 
in that latitude the day's length from sunrise to sunset 
must have been of fourteen hours. The hour is noon, 
the sun is over Gibeon, and the moon in its third 
quarter is in the west resting above the valley of 
Ajalon. 

The army of Israel has already that morning 
completed a twenty-mile march fromGilgal to Gibeon. 
It has with little difficulty raised the siege of the latter 
city. The besieging forces of the Canaanite kings 
have taken to flight towards the west and it is neces- 
sary for Josue's purposes that he should complete 
his task by overtaking these fleeing armies and crush- 
ing them. His own men are fatigued from their long 
morning march. To physical fatigue is added the 
trying circumstance of the burning rays of the noon- 
day sun. 

It is in this moment of crisis that Josue prays to 
heaven for miraculous aid. He bids the sun "be 
silent," for this is the literal meaning of the Hebrew 
word, that is, as Maunder interprets it, to cease to 
pour down on the earth its exhausting heat ; and this 
part of his prayer is answered at once by the fill- 
ing of the sky with clouds, from which, as the Bible 
relates, great hailstones descend upon the retreating 
Canaanites. 

The Lengthening of the Day. Refreshed by the 
cooler atmosphere divinely provided, the hosts of 
Israel begin the pursuit of the enemy. On top of a 
morning march of twenty miles, they are able to add, 
through strength that only God could have provided, 



Miracle of Josue. 143 

an afternoon pursuit of twenty-seven miles, for such 
is the remarkable distance that the geography of the 
region proves to have been covered. God was truly 
fighting for Israel and in a sense had obeyed the 
voice of a man. 

When afterwards the Israelites came to look back 
on that extraordinary march, they could only explain 
it by saying that the sun had in their favor stopped 
in its course. Be it remembered that they had with 
them no clocks or other timepieces by which to estimate 
the length of that momentous afternoon. They could 
measure it only in terms of the miles they had covered 
and the space traversed from noon to nightfall was 
equal to a full day's journey. 

Truly could they affirm that "there was never before 
or after so long a day." How often with ourselves 
does one day seem subjectively longer than another! 
Effectively for them the sun had stopped in its course 
or rather retarded its speed, for the word stopped 
needs not be taken too literally. With such unwonted 
and unaccountable speed did they cover the ground 
under divine help, that the sun appeared to move 
more slowly than ever before. 

Or better still, allowing for the poetical character 
of the composition, we may believe that they chose 
by a flight of fancy to express the effective length of 
that afternoon in imaginary terms of the sun's motion. 
When victims of ennui, do we not say, How slowly the 
hours creep on? and were we poets, might we not 
express it, The sun is moving slowly today? Sim- 
ilarly, the Jews kept the recollection of that prolonged 
interval in which they were able to accomplish so 
much for God. A half day had been turned by 



144 Miracle of Josue. 

miraculous intervention into a complete day, and it 
was with a certain truth that they could affirm with 
adoring wonder that on the occasion of their battle 
with the Canaanite kings the sun "hasted not to go 
down the space of one day." 

Appreciation of Maunder's Theory. So runs the 
interpretation of Maunder, an authority of repute and 
a trustworthy guide as being both a well-informed 
astronomer and a devout believer. It will help us 
respect his opinion to know that he is by no means 
reluctant to concede an astronomical miracle where 
one is plainly affirmed. He sees, for example, in the 
Star of Bethlehem a purely miraculous event not to 
be explained by nature's laws, but due to God's 
providential intervention. When after minute study 
of the victory of Josue he concludes it to have been 
a miracle not of the astronomical order, but accom- 
plished in other ways, his opinion is worth considering. 
It is particularly interesting as taking into account 
the plainly miraculous nature of the incident recorded 
and also allowing for the poetical character of the 
narrative without reducing the latter to the level of 
mere poesy and fiction. 

Conclusion. Till the Church has supplied an 
authoritative interpretation of this important narra- 
tive, it would seem that we are free to choose among 
the various interpretations. No interpretation, how- 
ever, would appear to be logical or acceptable that 
would rule out from this incident every element of the 
miraculous. For it seems to us plainly taught that 
on that famous "long day," God obeyed the voice 
of a man and fought for Israel. 



CHAPTER XV. 
THE FATHERS AND ASTRONOMY. 

By the Fathers we understand in general the 
Christian writers of the first period in the Church's 
history. In the West the period may be held to have 
terminated with Isidore of Seville of the seventh 
century, and in the East with John of Damascus of the 
eighth. The important writers of this epoch number 
between fifty and a hundred, and their works con- 
stitute, as may be imagined, a body of literature of 
vast extent. 

Our only present concern is to learn, if possible, 
what was the general attitude of this army of ec- 
clesiastical writers towards the physical sciences, 
especially the science of astronomy. Explicit treatises 
on astronomy we shall not, indeed, expect them to 
supply. For their works when massed are seen to 
constitute a library of theology, and in such a collec- 
tion we should no more look for scientific treatises 
than in a modem library of law. But inasmuch as the 
Fathers of the Church have been accused, by Andrew 
D. White and others, of having stayed and even 
thwarted the advance of science, it becomes the interest 
and the duty of the apologist to hunt up their scientific 
allusions that he may learn to what extent the charges 
made are true. 

145 



146 Fathers of the Church. 

The Standstill of Science. It has often been alleged 
as derogatory to the accomplishments of the Fathers, 
that they contributed nothing to the progress of 
scientific knowledge. From our modem standpoint 
we may be tempted to esteem this failure of theirs 
a cardinal sin. But it would be wrong, in this instance 
as in every other, to render a verdict of guilt too 
hastily. We of the twentieth century are prone to 
forget that there are other fields of profitable intel- 
lectual exploration besides the physical, and that there 
may be objects of research and thought worthier of 
study than the material world. 

The Fathers of the Church were philosophers and 
theologians, occupied with the problems of the world's 
origin and destiny, higher themes, surely, than any 
with which physical science is concerned. It is the 
fashion of the day to praise the ancient Greeks at the 
expense of the patristic and medieval theologians. 
But the distinction is to a large extent inconsistent, 
since both bodies of writers were at work upon the 
self -same themes. Philosophers like the Greeks, the 
Fathers were like them moralists as well, engaged in 
the elaboration of right rules of conduct. Finally, 
imlike the Greeks, the Fathers were Scriptural scholars, 
many of them of extensive erudition, in homily and 
commentary expounding with wonderful assiduity 
the Sacred Books in which they believed that God had 
given His revelation to man. 

Analogous Examples. Should we be surprised, 
then, if men so occupied failed to add much to the 
world's store of scientific knowledge? Though it were 
admitted, as it cannot be in its entirety, that they 
left physical science just where they found it, could 



Fathers of the Church. 147 

not an explanation be discovered that would exonerate 
them from all blame? To justify such an apology, 
we do not even need to transport ourselves in spirit 
back to their time, a process which, however, strict 
fairness would demand. But in our own era we can 
think easily of dozens and hundreds of men of highest 
respectability and most beneficent accomplishment, 
men of books and men of affairs, jurists, statesmen, 
historians and others, who have themselves done 
little or nothing for the onward march of Science. 
That the careers of these men are profitless, who shall 
allege ? 

Again, the present writer has often thought of the 
almost parallel example of the ancient Romans. 
It makes their history but little less illustrious to 
learn that this conquering people did nothing for 
Science's advance. Till Pliny of the first century after 
Christ, what Roman was a scientist? They were a 
nation of soldiers, statesmen, orators and jurists, 
and for seven hundred years they pursued through such 
avenues their triumphant course. Yet what writer 
of today rises to charge them with a cardinal sin, 
because Science remained at a standstill among them 
for full seven centuries ? With these seven centuries 
can we not properly compare the later seven in which 
the Christian Fathers were the teachers of the civilized 
world ? 

Heritage from the Greeks. Objection will be made, 
no doubt, that the Fathers began their career with a 
fairer start than the Romans, forasmuch as they were 
the direct heirs of the astronomy and physics of 
ancient Hellas. And they will be incriminated with 
having abused their precious heritage, by not merely 



148 Fathers of the Church. 

letting it lie fallow but by raising every possible 
obstruction to its further cultivation. Such is the 
tenor of Andrew D. White's accusations against 
them. 

This well-known writer smiles at the puerilities of 
patristic science. He cites from among them Cosmas 
of Egypt as having propounded a perfectly childish 
theory of the structure of the earth and grafted it on 
the science of theology. The ready answer to this 
particular charge is that Cosmas' conception of the 
universe belonged to cosmogony and not theology, 
and further that it had no influence on subsequent 
thought. Returning to the general arraignment, 
White rebukes the Fathers for having clung so 
tenaciously to false opinions regarding the shape of the 
earth, the motion of the heavens, and the nature of 
the firmament. And, most seriously of all, he charges 
the Fathers with indifference and even hostility to the 
study of science itself. 

In a few short paragraphs it is impossible to give 
an adequate rejoinder to these damaging complaints. 
But they demand some sort of reply, however in- 
adequate it be, as emanating from an American 
scholar and statesman of high rank, and embodied 
in a work that has free and wide circulation among 
our college students. 

DEFENCE OF THEIR DOCTRINE. 

The first palliation for the reputed offence of the 
Fathers is that whatever false science they retail, 
was practically all of it derived from the very sources 
which it is the fashion of the day to laud in the 



Fathers of the Church. 149 

highest degree. As far as was consistent with their 
faith, the Christian Fathers were the pupils of the 
Greeks. It was the latter and not the patristic 
writers who invented the false theories of a solid 
firmament and a motionless earth. If Europe and 
Arabia down to the Renaissance believed in the 
Geocentric system, it was because they trusted 
Ptolemy the Greek, till then admittedly the greatest 
of astronomers. And a similar ancestry could be 
traced, we venture to say, for all or the major part 
of their scientific errors as far as these may have 
extended. 

Restrictions Made by the Fathers. But if the 
Fathers were in general the heirs of the Greeks, they 
were not guilty of the mistake of accepting the inheri- 
tance in its entirety. To a large extent they could 
discern the chaff from the wheat, and were actually 
at pains to make the separation. It ought to be 
known that the scientific literature of the Grecians 
is teeming with the wildest and vainest of speculations 
regarding all matters within the scope of astronomical 
science. Here as elsewhere, the Greeks speculated 
endlessly, contradictorily, emptily, and almost aim- 
lessly. In unfounded speculation they discoursed 
on all manner of astronomical subjects, the shape 
and size and distance of the sun, its nature and that 
of the moon and stars, and so on almost indefinitely, 
with scarcely any agreement or concomitance of 
opinion. There were almost as many diverse opinions 
as there were men. 

To this motley assemblage of groundless and con- 
flicting theories the Fathers had full access through the 
medium of Plutarch, the Greek compiler. Eusebius, 



150 Fathers of the Church. 

for example, the Father of Church History, quotes 
Plutarch on just these topics for over thirty pages. 
If Eusebius and the other Fathers grew impatient 
with all this ill-assorted mass of soi-disant science, 
shall we charge them as Dr. White does with having 
been false to the interest of science? Should we not 
rather maintain that they helped save science from 
its enemies? 

Opposition to Science. It is only in the light of 
these indisputable facts that we can understand the 
sayings of the Fathers in which, as quoted by White, 
they upbraid science for its inutility. Be it noted 
in passing that White is wont to quote them not 
literally but freely, and apart from their context. 
Lactantius, Eusebius, Augustine, and Basil, these are 
the four whom he selects as representative. They are 
truly representative, and indeed any one of them 
might stand for all. 

Let Eusebius be our particular choice, for he 
discusses astronomy more completely than the others. 
White alleges (Warfare, Vol. I, p. 91) that Eusebius 
endeavored to bring scientific studies into contempt, 
and quotes him as saying, "It is not through 
ignorance of the things admired by them (scientific 
investigators) , but through contempt of their useless 
labor, that we think little of these matters, turning 
our souls to better things." 

Who would guess from this brief epitome of 
Eusebius' views that the latter had devoted to the 
subject more than thirty pages? Who could possibly 
surmise that he had taken pains to write out, under the 
guidance of Plutarch, all the known opinions of the 
Greeks on some thirty-nine problems, all but two or 



Fathers of the Church. 151 

three of them astronomical? Let the curious read 
Eusebius for themselves in the fifteenth book of his 
Praelectio Evangelica. They will there discover, 
what White might well have acknowledged, that on 
not one of the problems are the Greek philosophers 
in agreement. On the nature of the sun there are 
nine opinions, on its size four, on its shape an equal 
number, on the moon's nature seven. And this 
discrepancy of judgment continues to the end. More- 
over, a large proportion of the theories are of the most 
fantastic sort. 

In the face of this chaotic wilderness of diverse, 
fluctuating and contradictory teachings, what could 
Eusebius do but turn away in impatience, and take 
up in their stead the only truth of which he felt 
certain, the truth of the Gospel? Such was his actual 
procedure. "Does it not seem to you that we have 
rightly and deservedly departed from the curiosity 
of all these men, so idle and so full of error?" He 
confesses frankly that he can see no fruit or utility 
for man in the teachings he has quoted. And he 
appeals for his complete justification to Socrates, 
the wisest of the Greeks, who in his day had adopted 
precisely the same stand. This and no other is the 
argument and spirit of Eusebius. 

No Opposition to True Science. This was the 
temper, also, that actuated the other Fathers named, 
Lactantius, Basil, and Augustine. No doubt these 
men valued spiritual knowledge above material. But 
it by no means follows from this that they tmder- 
valued Science. They were scholars of extensive 
culture, Basil a graduate of Athens, Augustine of 
Carthage, and Lactantius styled because of his 



152 Fathers of the Chixrch. 

proficiency the Christian Cicero. They were well 
acquainted with the learning of the Greeks. That 
they rebelled against the scientific fantasies of the 
latter, is not a proof that they were hostile to the ad- 
vance of Science itself. 

In the Imitation of Christ, Thomas a Kempis ex- 
presses a sentiment quite similar to theirs. "Surely 
a humble husbandman that serveth God, is better 
than a proud philosopher who, neglecting himself, 
is occupied in studying the course of the heavens." 
Like the Fathers, k Kempis had reason to be disgusted 
with the astronomy of his time, for it was beginning 
to be impregnated again with the virus of Astrology. 
By refusing to follows such pseudo-scientific teachings, 
both k Kempis and the Fathers did a real if seemingl}^ 
negative service to the science of astronomy. 

THE FATHERS AND ASTROLOGY. 

"He was bom under a lucky star." Language of 
this sort, used now only in pleasantry, recalls a form 
of superstition which was once accepted seriously by 
all men throughout the civilized world. In many a 
period, mankind has believed literally that the stars 
and planets exercised a real influence in shaping 
human lives. And there have been many epochs, an- 
cient, medieval, and even modem, when astrology, 
the telling of fortunes by the stars, was given a rank 
among the learned professions. 

Even now there occur occasional sporadic outbreaks 
of the same superstition. Along with other quacks 
and necromancers, astrologers are still occasionally 
in evidence, advertising their trade through the 



Fathers of the Church. 153 

columns of the press. Indeed it is affirmed by the 
Catholic Encyclopedia that the growth of occultistic 
ideas is reintroducing astrology into society. 

Errors of Astrology. Whatever the popularity of 
this practice in the past, and whatever its prospective 
vogue in the near future, it is to be set down without 
qualification or hesitation as a delusion and a snare. 
To suppose that the heavenly bodies have an influ- 
ence on human conduct is in its origin a pagan error, 
closely allied with the pagan myth that the sun, moon 
and stars are presided over by as many separate deities. 
Only thus could have originated the delusion that 
Jupiter and Venus would procure a blessed destiny, 
and Mars and Saturn a troubled one, for the children 
bom at the time of their rising. 

Nor can the cult be justified by an array of the 
names of those who have been its votaries. It is true 
that many astronomers in the past, including the great 
Kepler himself , have practised the astrological art, cast- 
ing horoscopes for their clients. But in most cases it 
would be found, at least in the modern period, that 
these scientists merely yielded through tolerance to the 
weakness of their age. In true astronomy there is no 
place whatever for astrology. 

Besides being groundless, the practice is to be con- 
demned for its perilous moral tendencies. Distract- 
ing the soul from the worship of the spiritual God, 
who alone governs the universe, it substitutes for His 
action that of mere material objects, stars and planets, 
which it thus elevates to the rank of lesser gods or 
demons. Pretending to forecast from birth what 
each man's course in life shall be, it robs the will of its 
proper share in moulding human conduct. 



154 Fathers of the Church. 

The Christian Fathers. An interesting testimony 
to the former prevalence of this erroneous belief is 
found in one of Sir Walter Scott's novels, "Guy 
Mannering," whose whole plot turns upon the fulfil- 
ment of an astrological prediction. Reading the his- 
tory at hand the novelist had learned what complete 
sway the cult had formerly exercised, almost down 
to the time of his writing. It would have interested 
the celebrated author to know that there was, how- 
ever, one long period of history in which astrology was 
absolutely and effectually excluded from Christian 
Europe. For over a thousand years Christendom re- 
mained free from this blight, thanks to the teachings 
of the Fathers of the Church. 

In discussing the relations of the Fathers towards 
the astral science, we have already shown how they 
purged it of some of its grossest errors. But their 
principal service to the science remains now to be told. 
For amongst all the vagaries of the science of the 
heavens, astrology is both in theory and in practice 
the most deplorable. That the Fathers placed the 
weight of their great authority in the scale against 
this superstition, is one of the most praiseworthy of 
their achievements. 

First Efforts at Reform. At the time that the 
Fathers began to write, in the century just following 
the labors of the Apostles, astrology formed every- 
where an integral part of the science of astronomy. 
It was taught in all the schools, Chaldean, Jewish, 
Grecian and Roman. Almost from the beginning the 
defenders of the Christian faith proceeded to attack 
this pernicious error, realizing how inimical it was to 
the spread of the truth which Christ had come to im- 



Fathers of the Church. 155 

part. Already in his address to the Greeks, Tatian 
was heard denouncing the absurdities of Grecian 
astronomy and astrology. This was in the middle 
of the second centur^^ just at the close of what is 
called the Apostolic Period. 

A little later, Tertullian, the famed apologist of the 
then flourishing African Church, placed himself on 
record as the uncompromising enemy of astrology. 
With his usual vehemence of language he declared 
that ''of astrologers there should be no speaking even " 
among Christians; and went to the length of saying 
that "he cannot hope for heaven whose finger or wand 
abuses the heavens." These and many similar utter- 
ances may be found in his Treatise on Idolatry, 
ch. ix. 

Respect for True Astronomy. With this denuncia- 
tion of magic and idolatry there went hand in hand, 
however, a genuine respect for the proper science of 
the heavens. Contemporary with Tertullian, and 
like him one of the great Christian masters of the 
period, was Clement of Alexandria. To the Catho- 
lic astronomer of today it is gratifying to find 
this Father of the Egyptian Church giving gener- 
ous testimony to the worth of astronomical science. 
With just discrimination he praises astronomy as 
"leading the soul nearer to the creative power, as 
helpful to navigation and husbandry, and as making 
the soul in the highest degree observant, capable of 
perceiving the true and detecting the false." Miscel- 
lanies, bk. vi. ch. ix. 

Another contemporary, Hippolytus, was indeed 
unsparing in his denunciation of astrology. In a 
treatise of eleven quarto pages, contained in his "Refu- 



156 Fathers of the Church. 

tation of All Heresies," he riddled with merciless 
logic the vain pretensions of the Greek astrologers. 
But he showed that he had no quarrel with a well- 
ordered study of the heavens, by giving liberal praise 
to Ptolemy, the ablest of the astronomers. 

A Universal Teaching. In far distant Syria, then a 
choice realm in the Church's patrimony, there was at 
the beginning of the third century another school of 
Christian philosophers who joined with their brethren 
in West and East in waging war on the same dread 
enemy. A Syrian work, called the Book of the As- 
trologers, has two quarto pages of excellent quality 
recounting and scoring the absurdities of current 
astrological practices. It is so like Hippolytus' work 
that one seems an echo of the other. 

Perhaps the most interesting of all these concordant 
denunciations is that found in the "Recognitions of 
Clement," a patristic writing probably of the third 
century. Here the treatises on astrology run to full 
ten chapters, a sign that the author had abundant 
knowledge of the subject. In this work astrology 
is refuted particularly from the moral point of view. 
It is convicted of the double charge of being fatalistic 
in its tendency and subversive of all morality. " Men's 
conduct," says the author's thesis, "is due to their 
own free will and not to the configuration of the 
planets." 

Golden Age of Patristic Literature. So ran on in 
perfect unity and harmony the steady flow of patristic 
teaching. It reached its climax, as we should expect 
to find, in the heroic writers of the fourth century, the 
golden era of patrology. Lactantius, the Christian 
Cicero, re-echoed the voices of the past in pronouncing 



Fathers of the Church. 157 

astrology the work of demons. And Augustine, the 
greatest of the Fathers, confirmed the decision of his 
predecessors by protesting against the amalgamation 
of astrology with the true science of nature. 

So effectual indeed was the opposition to astrology 
of the earlier Christian writers, confirmed by the mas- 
ters of the post-Nicene period, that the practice came 
to be regarded by all the faithful as a superstition and 
a danger, and continued to be so esteemed down to the 
time of the Crusades. For a full millenium, Christian 
Europe midst all its vicissitudes was spared the absurd- 
ities of astrological belief and practice, thanks to the 
patristic school of writers. 

A Surprising Omission. We have thought it well 
to bring to light these none too well known facts re- 
garding one important part of the astronomical teach- 
ings of the Fathers. How they could have escaped 
the attention of Andrew D. White, or how he could 
have failed to find place for them in his voluminous 
work, it is difficult to understand. 

His book bristles with accounts of superstitions, 
always telling against the theologians and in favor 
of the scientists. But astrology is absent even 
from the index of his work. Had he allotted it a 
chapter, his numerous readers would have learned 
that one great school of theological writers, enduring 
for a thousand years, did wage war on a certain sort 
of science, to wit, the pseudo-science of astrology. 



CHAPTER XVI. 
ASTRONOMY IN THE MIDDLE AGES. 

As the title indicates, this chapter is intended to 
relate how the science of astronomy fared in the Mid- 
dle Ages, the long interval of a thousand years stretch- 
ing frora the fall of Rome in 476 to the fall of Constan- 
tinople in 1473. The period was for the most part, 
it must be confessed, rather a barren one for the 
science. Miss Gierke passes it by without mention 
in her article on Astronomy in the Catholic Encyclo- 
pedia, and Sir Robert Ball finds in this epoch no name 
worthy of a place in the list of the world's great 
astronomers. But somehow and somewhere the 
science was preserved; just how and where, suggests 
a not uninteresting chapter. 

First of Two Periods. For convenience the thou- 
sand years should be divided into two great periods 
of about equal length. Of the earlier epoch, ending 
with the year 1000, it is customary to suppose that 
it contributed nothing to the science of astronomy. 
In the sense of original achievement, this may hold 
true. But it would be quite false if interpreted 
to mean that the study of astronomy was entirely 
neglected. Even original achievement of a certain 
kind was not altogether wanting. 

The regulation of the calendar has always been 
considered one of the chief offices of astronomy. 

168 



The Middle Ages. 159 

When Dionysius Exiguus, therefore, in the sixth cen- 
tury instituted a new chronology in which the years 
were dated from the birth of Christ, and again when 
he determined the date of Easter from year to year by 
applying the so-called Metonic Cycle, he initiated 
changes which most certainly belong, and in no un- 
important way, to the annals of astronomy. 

Astronomy in the Schools. Original accomplish- 
ments apart, the amount of attention given to the 
science was greater than is generally supposed. The 
early medieval period cannot properly be called a 
Dark Age as far as astronomy is concerned. Even 
though we have not evidence that there was exten- 
sive observational study of the heavens, we have 
plenty of evidence that the science was cultivated 
with sufficient assiduity in the class-room. If we may 
trust the medieval programme of studies, astronomy 
was taught in every monastic school without excep- 
tion. It was one of the branches universally pre- 
scribed. The seven ' * liberal arts , ' ' which every school 
curriculum must include, were Grammar, Rhetoric, 
and Logic, making up the so-called Trivium, and 
Arithmetic, Geometry, Music, and Astronomy, called 
the Quadrivium. 

These studies had to be followed by all who fre- 
quented the schools, not only the boys who were pre- 
paring to be monks and who lived therefore within 
the cloister, but also the children who came from out- 
side, and were intended for life in the world. These 
youths were put through a course of mental training 
which appeals even to some present-day educators 
as excellent in its general scheme. 

What concerns us most here, is that Science had its 



160 The Middle Ages. 

fixed place in the scheme, being represented by the 
mathematical sciences of arithmetic and geometry and 
the physical science of astronomy. Science of some 
sort, then, had its allotted place in the ordinary curric- 
ulum of the monastic schools, whose general standard, 
be it remembered, remained unchanged for centuries, 
indeed, if we mistake not, to the end of the Middle 
Ages. 

Character of the Instruction. It may be thought 
that the instruction given in the science of astronomy 
was of the most elementary sort. It will perhaps be 
argued that the teaching must have been of this de- 
scription since it was designed to meet the needs of 
mere boys and striplings. Though the rudimentary 
character of the instruction were to be confessed, 
however, this would not alter the fact, or weaken our 
contention based on it, that the science was taught in 
some fashion in all the schools and to all the pupils. 
Can higher or even equal claim be made for our gram- 
mar schools of today respecting the science of astron- 
omy? 

But the instruction was probably not so elementary 
as we have been inclined to believe. It was always 
the interest of the Church to encourage acquaintance 
with the science of astronomy, on which she depended 
for the determination of the dates of her movable 
feasts. When instructing her children in the liturgy, 
therefore, she would be at pains to have them under- 
stand how the days for Easter and the other festivals 
were computed. 

Further, as we gather from the writings of many 
of the Fathers, astronomy was esteemed one of the 
noblest branches of knowledge. St. Isidore of Seville 



The Middle Ages. 161 

said of it that it detaches the mind from earthly things 
and fixes the mind in the contemplation of what lies 
above. With such sentiments animating them, we 
may feel sure that the medieval Christian teachers 
could not have been content with a mere perfunctory 
teaching of the science. 

Medieval Text Books. The mode of instruction is 
best surmised from the literary relics of the period, 
which include occasional treatises on astronomy. 
The latter are usually epitomes or primers, evidently 
designed for the use of the schools. We are told that 
in the monasteries no authors had higher repute as 
educators than Cassiodorus of the sixth century and 
Isidore of Seville of the seventh, both of whom com- 
posed summaries of astronomy that are still extant. 
The treatise of the former would cover about four 
pages of a modem schoolbook, that of Isidore about 
twenty pages. Until the eighth century, it was from 
these manuals or others similar to them that the 
teacher instructed his classes. 

Short as are these chapters, they contain or suggest 
a fair amount of astronomical infomiation. Based 
on Ptolemy, they teach of course the science of ap- 
pearances. They suppose the heavens in motion and 
the earth at rest. Isidore makes the additional mis- 
takes of supposing that the stars receive their light 
from the sun, and that comets are portents of evil. 

Their Good Features. But for the most part their 
teachings are, if simple, yet sane and correct. They 
estimate the sun correctly as larger than the earth, 
and the latter as larger than the moon. They explain 
rightly the causes of eclipses both of the sun and moon. 
They distinguish properly between stars and planets, 



162 The Middle Ages. 

Isidore supplying moreover a pretty complete enum- 
eration of all the constellations and all the planets. 

The general utility of the study is particularly well 
expressed by Cassiodorus, who reckons among its uses 
the forecasting of the weather, the keeping of time, 
the determination of the paschal feast, and finally the 
proper understanding of solar eclipses that simple 
people may not be disturbed or frightened when these 
occur. Elementary, then, as are these expositions 
and even unoriginal, they are, it appears to us, wise in 
their selection of materials and well-suited to the 
purpose for which they were created. 

One excellence in these little manuals that ought 
not to be overlooked is their protest against the abuses 
of astrology. Distinguishing correctly between "na- 
tural" astrology, the forecasting of the weather, and 
"judicial" astrology, the forecasting of men's lives, 
both of them reject and condemn the latter as false 
and even contrary to the faith. And this remained 
the attitude of the Church, we have reason to believe, 
throughout the earlier medieval period. 

St. Bede and His Followers. Far more elaborate 
treatises on astronomy appeared in the eighth cen- 
tury from the pen of St. Bede, the pride of the English 
Church and the most scholarly man of his time. These 
compositions, intended some for professors and others 
for pupils, would constitute in modem print an octavo 
volume of fully five hundred pages. Of the same 
doctrinal tendency as the earlier treatises mentioned, 
they are far more learned, abounding in textual details 
and in apposite diagrams and illustrations. A recent 
article in the Catholic University Bulletin informs us 
that St. Bede's manual became the most popular one 
in the classes of astronomy. 



The Middle Ages. 163 

The valuable educational work of St. Bede was sup- 
plemented by that of Alcuin of England and Rabanus 
Maurus of Germany, who flourished respectively in the 
latter half of the eighth century and the first half of 
of the ninth. Both of these monks were teachers of 
renown, and composed manuals on the seven liberal 
arts, including astronomy, suited to the particular 
needs of their pupils. 

The Monastic Ideal. From all that has been related 
above it would appear that in Christian Europe during 
the early Middle Ages fair attention was given to the 
science of astronomy. In the collapse of the other 
physical sciences as far as this may have occurred, 
astronomy did not share. No doubt the work of the 
schools, as every other peaceful enterprise, was des- 
tined to suffer much during the ninth and tenth cen- 
turies from the devastating invasions of the Danes 
and Normans. 

But the monastic ideal was never entirely sub- 
merged, and this ideal, with its threefold exhortation 
to prayer, manual labor and study, remained the sav- 
ing influence of the Middle Ages, even in its darkest 
days, and ultimately effected the civilization and 
Christianization of the barbarian tribes of the north 
and of all Western Europe. 

LATER MIDDLE AGES. 

That there was some cultivation of astronomy on 
the part of Christians in the early Middle Ages, our 
previous section has, we think, sufficiently demon- 
strated. This section insisted on the fact that in the 
monastic schools then dominant, astronomy was one 



164 The Middle Ages. 

of the studies universally prescribed. For aid in the 
study, it was further urged, handbooks and treatises 
were provided b)- some of the best of the medieval 
educators. 

Limitations and Their Reason. If the instruction 
lacked the fullness that other times and places have 
exhibited, the explanation is not that the Church or 
the medieval Christians were averse to learning, but 
that Christians of the Latin rite had gradually lost 
acquaintance with Greek, the language of practically 
all the early masterpieces in astronomical science. 
Latin, the language of the ancient Romans, had come 
to be the current means of communication in all the 
lands of Western Europe, particularly in the schools. 
Now the ancient Romans, as we have already had 
occasion to remark, were but little if at all devoted to 
the physical sciences and left no scientific monuments 
of worthy character. 

If, again, learning suffered a decline in the ninth 
and tenth centuries, the reasons were political rather 
than theological. The terrible descent of pagan and 
barbarian Danes and Normans on the coasts of France 
and the British Isles, undid for the nonce the salutary 
accomplishments for education of the preceding cen- 
turies. What Christian missionaries and teachers had 
done for the first hordes of barbarian invaders, in 
civilizing the Goths of the continent, the Vandals of 
Africa and the Saxons of England, this beneficent 
work the Church must begin again in favor of the 
Huns of the East and the Danes and Norsemen of the 
North. It was inevitable that, while the task of their 
amalgamation and Christianization was in progress, 
learning and scholarship should suffer. 



The Middle Ages. 165 

Career of the Arabians. Meantime in another part 
of the world, dominated by an aHen and inferior 
reHgion, science found a temporary refuge. We do 
not need to sympathize with the religion of the Ara- 
bians, that of the prophet Mohammed, to admire the 
services they rendered to physical science in the medi- 
eval period. It would be going against the facts of 
history not to acknowledge that physical science owed 
its preservation during the Middle Ages chiefly to the 
schools and scholars of the Arabian or Mohammedan 
Empire. 

What a wonderful and indeed romantic history was 
that of the Arabians during this era. In military 
annals the seventh century and the first two decades 
of the eighth were the period of Arabian glory. In 
the hundred years from the Flight of Mohammed in 
622, they effected the conquest of southeastern Asia, 
all northern Africa, and Spain, all told of half the 
civilized world. Their empire established, they had 
then settled down in a measure to the more peaceful 
pursuits of commerce and learning. 

Transferring now their caliphate or seat of govern- 
ment from Damascus in Syria to Bagdad in Mesopota- 
mia, they soon made of the latter the grandest city in 
the world, a metropolis of well-nigh two million in- 
habitants, the world's chief centre of government, 
commerce and scholarship. A century or more later, 
there was established an independent caliphate at 
Cordova in Spain, which was destined to rival the 
eastern metropolis in its devotion to learning, and 
which became one of the channels through which 
scientific knowledge streamed back into Christian 
Europe. 



166 The Middle Ages. 

Their Service to Astronomy. We write "streamed 
back" advisedly, for it is not to be forgotten that it 
was from Christian hands that the Arabians received 
in the first instance the treasures of Hellenic science. 
The Arabians came late into the field, and owed to the 
Christians of Damascus in Syria and of Alexandria in 
Egypt their first acquaintance with the Grecian mas- 
ters. If Eudoxus and Hipparchus and Ptolemy were 
now put into their hands, it was because the produc- 
tions of these geniuses as well as all the other master- 
pieces of Greek literature had been carefully guarded 
for many centuries by the Christians of the East. But 
the credit belongs to the Arabians that they proved 
not unworthy custodians of this priceless heritage. 
Some of their particular achievements in astronomy 
must find a place in our narrative. 

To this interesting people we owe the Arabic nu- 
merals, so much more convenient than the Roman. 
We ow^e them some of the commonest words in astro- 
nomical terminology, such as almanac, azimuth, 
zenith and nadir, as well as the actual names of many 
separate stars, as Algol, Aldebaran, Vega and Deneb. 
Their name is written large in the vocabulary of the 
science. Moreover they constructed calendars and 
predicted eclipses, using for the latter purpose the 
Saros cycle discovered by the Babylonians perhaps 
two thousand years earlier. Finally they pursued 
the detailed study of the constellations with the 
assiduity for which the Orientals have been famed 
in many a period of history. 

It may not be claimed, however, that they contri- 
buted notably to the progress of the science. They 
lacked the qualities of originality and inventiveness. 



The Middle Ages. 167 

Not only was Ptolemy their acknowledged naaster, 
but his works were esteenied too sacred to allow any 
alteration at their hands. A further defect in all their 
astronornical work was its coniplete subordination 
to the superstition of astrology. Devotion to the 
latter delusion seems to have been in keeping with all 
the traditions of their race. 

Arabic Influence in Europe. There can be no doubt 
that it was from the Arabians that Christian Europe 
came later to learn again the science of astronomy, 
when the terrors of barbarian invasion had passed 
away. The most scholarly man in Christendom at 
the end of the tenth century was Gerbert, who had 
received his schooling in the Arabian colleges of Spain, 
then in the zenith of their glory. A happy event is it 
in Church history that in the pivotal year 1000 Ger- 
bert, the scholar, under the name of Sylvester II, 
was reigning as Pontiff over all Catholic Christendom. 

The example of Gerbert is but one indication of 
many that Spain was the avenue through which the 
riches of astronomical lore fotmd their way back to 
Christian Europe. The first observatory in Europe, 
a structure of palatial grandeur if the engravings are 
to be trusted, was erected at Seville in 1196. A hun- 
dred years after, King Alfonso X of Castile drew up, 
with the help of Arabian and Jewish scholars, the so- 
called Alphonsine Tables, and won for himself an 
honored place in the history of the science. 

It is not, however, in the medieval period, even in 
its later centuries, that Europeans shall give evidence 
of astronomical achievement of original and progres- 
sive character. Their instruments for observation 
were still of the crudest sort. The optical lenses 



168 The Middle Ages. 

invented by Roger Bacon in the thirteenth century, 
must wait for over three hundred years before being 
put to Vise by GaHleo in an astronomical telescope. 
Albertus Magnus, also of the thirteenth century, a 
student of nature through books, was hampered in 
his study of astronomy by being obliged to forage 
through poor, blundering, and second or third-hand 
translations from the Arabic of Ptolemy's Almagest. 
Worthy scientists as were both Bacon and Albertus, 
they were denied the means for advancing astronomy 
along proper lines. 

An Era of Astrology. Unhappily also, and this is 
from the Catholic viewpoint the saddest chapter in 
the entire history of astronomy, unhappily Europe 
had inherited from the Arabians the superstitions of 
the ancient astronomy as well as its excellences. Con- 
sequent on Arabia's bequest to Europe, there began 
in Christendom an era of astrology. From the twelfth 
to the fifteenth century the influence of astrology 
grew in force till it infected almost all classes of society. 
Astrology was the order of the day, as is frankly 
avowed and detailed by Pastor in his History of the 
Popes, and by Jacobi in the Catholic Encyclopedia. 

It mattered not that theologians of the stamp 
of Aquinas protested against it, reckoning it with 
other superstitions. Nor was the opposition of 
Petrarch sufficient to save Europe from its onset. 
St. Bemardine and other missionary preachers tried 
to stem the tide, but for the moment without avail. 
It was destined to run its course. In the troubled 
days of the fourteenth and fifteenth centuries astrol- 
ogy found too many willing adherents and for a time 
threatened even to become a substitute for the true 
religion. 



The Middle Ages. 169 

Overthrow of Arabic Influence. Astrology, how- 
ever, could not triurnph ultimately. Its essential 
falsehood, unperceived by Arabians, forced itself on 
Christian minds when Arabic influence began to wane. 
Its essential heathenism could not survive the partial 
resuscitation of paganism that was one feature of the 
Renaissance. There came the dawn of a better day 
when worthy astronomers, like Regiomontanus in 
Germany, and Cardinal Nicholas de Cusa in Italy, 
entered the field and paved the way for the radical 
reform which another Catholic ecclesiastic, Coperni- 
cus, was soon to initiate. The final issue would be a 
last sign proving the essential superiority of the 
Christian over the Mohammedan religion. For Chris- 
tianity makes for progress, Mohammedanism for 
stagnation. Christianity abhors superstition, Moham- 
medanism welcomes it. 



CHAPTER XVII. 
REFORM OF THE CALENDAR. 

As we emerge from the medieval into the modem 
period, we come upon two events in astronomical his- 
tory worthy of being penciled in high relief. The 
first, belonging to the theory of the science, was the 
the substitution of the Copemican for the Ptolemaic 
system. Of the vast significance of this departure, 
we have already spoken at length. 

The other, belonging to astronomical practice, was 
the reform of the calendar, consummated by Pope 
Gregory XIII. This pontifical act may well be em- 
phasized by Catholics not only because of its great 
scientific and practical importance, but still more 
because of its clear revelation of the attitude of the 
Church toward astronomy in the period just preced- 
ing the celebrated trial of Galileo. 

Pontifical Acts. Twice in history has the calendar 
been revised on truly scientific principles, first by 
Julius Caesar in 46 B. C, and again by Gregory XIII 
in 1582 A. D. In both instances, as Dr. William Barry 
happily observes, the reformer acted in his capacity of 
Pontifex Maximus or Supreme Pontiff of the received 
religion. In both instances the prime motive for the 
reform was the regulation of religious festivals. In 
each case it was the ecclesiastical calendar that was 
paramotmt in the Pontiff's mind. 

170 



Reform of the Calendar. 171 

Of necessity, however, the civil calendar was altered 
and regulated at the self-same niovement, a conse- 
quence which widens very much the interest of the 
event. And further, aside from motive or conse- 
quence, the reconstruction was in each case based on 
astronomical data, a procedure which entitles the 
achievement to a place of standing in the history of 
the sciences. 

Nature of the Calendar. The calendar is known to 
most persons as a printed set of tables, revealing at a 
glance the length of the year and of the months, and 
particularly the agreement of week-days with dates 
throughout the year. The current calendar, for ex- 
ample, tells us that this year (1909) shall consist of 
365 days, that February shall be of ordinary length 
and not increased, as in leap year, by one day, and 
that the first of January shall fall on Friday, a like 
fixation being indicated for every other date. 

Not everyone stops to think that underlying the 
calendar is a certain definite system of reckoning time 
and distributing it into its proper divisions. To be 
of permanent value the system used must be most 
carefully framed. An arbitrary or merely conven- 
tional system would not answer. In the last analysis 
the method must rest on the divisions of time that 
nature itself supplies. When, however, as often hap- 
pens, the natural divisions are unequal or fractional, 
it is permitted to use an average result. 

Of our four larger divisions of time one, the week, 
is indeed purely conventional, bearing no relation 
whatever to any fact in nature. But the remainng 
three are founded on astronomical facts, the year 
being based on the sun's apparent circuit among the 



172 Reform of the Calendar. 

stars, the month on the moon's similar but swifter 
journey, and the day on the sun's diurnal revolution. 
Of these the day and the year are clearly the two of 
greatest practical importance. The day determines 
the normal hours for labor and rest, while the year 
determines the seasons and consequently the times 
when the earth shall bring forth its fruits and in turn 
rest from labor. Both these determinations, be it 
noted, are absolutely independent of man's control. 
The calendar that neglects them or assumes independ- 
ence of them must inevitably perish. 

The Julian Calendar. Anciently all calendars were 
exceedingly imperfect. Judea, Egypt, Greece and 
Rome had each its own method of apportioning time, 
but the results were never better than approximate. 
One source of complexity and error was insistence on 
the month rather than the year as the unit of time 
measurement. The lunar month with its quota of 
29i days, could only by the most indirect methods 
be made to synchronize with a year of 365 days. 
So long as the month was emphasized and the 
year subordinated, a satisfactory calendar was im- 
possible. 

The first step in Caesar's reform was to give the 
year the place of preference in the calendar and to 
divide it arbitrarily into twelve calendar months of 
almost equal length. The course of the months no 
longer agreed with the course of the moon but was 
made to suit the year. The length of the months was 
no longer the 29J days of interval from one new moon 
to the next, but became 31, 30 or 29 days, according 
to the month, in such manner, however, that the sum 
of the twelve totaled 365 days. The wisdom of this 



Reform of the Calendar. 173 

substitution of an artificial for the natural month has 
commended it to all subsequent ages. 

A still more radical change had now to be made. 
Into such confusion had the calendar fallen that in 
Caesar's time there was a difference of some eighty- 
days between the calendar's reading and the sun's 
position in the heavens. To rectify this huge error, 
the emperor decreed that eighty additional days 
should be inserted in a certain determined year, that 
thus the calendar might be brought into alignment 
with the celestial events it was intended to represent. 
This abnormal year lasting 445 days has since been 
known in history as "the year of confusion." By 
its means, however, the equinoxes of the calendar and 
of the heavens were brought into harmony, and a 
fresh and proper start was effected. 

Exact Length of the Year. The most delicate part 
of the problem remained still to be solved. For the 
astronomical or true year, that is the time from equi- 
nox to equinox, measures not an even number of days, 
365 or 366, but a fractional number between the two. 
It was imperative that the length of the year should 
be determined with utmost accuracy before the new 
calendar rules were proclaimed. 

As in his earlier corrections, so in this determination, 
Caesar took counsel of the Greek astronomers of Alex- 
andria. On their computation that the solar year 
measures 365i days, he based his final ruling to the 
effect that, while the normal year should be composed 
of 365 days, every fourth year should have added to 
it an extra day, placed in February which was then 
the twelfth month, the result being what we now call 
a leap year. Thus was cohipleted the scheme of the 



174 Reform of the Calendar. 

Julian calendar, which remained the norm for all 
civilized nations down to the reign of Pope Gregory 
XIII. 

There would have been no need of a later reconstruc- 
tion of the calendar had the Alexandrian computation 
been completely accurate. But it was in error, by a 
small amount, to be sure, only the 1-128 part of a day, 
but enough to cause a variation from the truth of one 
day in 128 years. The discrepancy was sufferable for 
a time, but it necessarily continued to increase so that 
in the sixteenth century the error amounted to four- 
teen days. Reckoned from the Council of Nicaea 
of the year 325, which had fixed the rule for Easter, 
the variation was somewhat less, ten days instead of 
fourteen. The actual net consequence in Gregory's 
time was that whereas the vernal equinox was cele- 
brated in the calendar on March 21, in the heavens it 
occurred ten days earlier, on March 11. 

The Gregorian Calendar. As Easter day was deter- 
mined by Church law from the vernal equinox, this 
increasing error became a matter of solicitude to the 
Roman Pontiffs. A century before Gregory, they 
had begun to institute means for making the proper 
corrections. They engaged the services of the ablest 
astronomers of the time, as Regiomontanus in the 
fifteenth century and Copernicus in the sixteenth. 
With wise caution they delayed decision till all the 
required data had been accurately ascertained. 
Finally in the year 1582, Pope Gregory XIII, applying 
the finished results of the Jesuit astronomer, Fr. Cla- 
vius, proclaimed the calendar that bears his name. 

His alterations did not need to be so radical as 
those of Caesar, but in two respects they were the 



Reform of the Calendar. 175 

same in kind. The immediate error he corrected by 
dropping outright ten days from the year 1582, skip- 
ping at once from October 4 to October 15. The 
intervening dates will be found nowhere in Catholic 
history, owing to the summary but wise excision 
made by the Holy Father. 

To prevent recurrence of error, he further decreed 
that thereafter the centesimal years, as 1700, 1800 
and 1900 should not be leap years, unless they were 
evenly divisible by 400, as is the case with 1600, 
2000 and 2400. We owe it to Gregory, therefore, 
that 1900 was not a leap year and that 2000 will be 
one. In general we owe him an adjustment of the 
calendar as nearly accurate as possible. If the slight 
error of one day in 3,325 years was permitted to 
remain, it was that the rule determining leap years 
might be a convenient one and easily applied, and 
because it was felt that the error that will have arisen 
after 3,000 years have passed can easily be corrected. 

Churches Attitude Towards Science. Gregory XIII 
has no calendar month named after him as has Julius 
Caesar, but his name is immortalized in the proper 
title of the calendar under which we now live. It is 
pleasant to note that the honor of reforming the calen- 
dar in modem times fell to one who was at once a 
benign ruler and a warm patron of learning. It does 
not detract from his honor to say, however, that his 
accomplishment was but the final step in a papal en- 
terprise that had been maturing for a hundred years. 

This enterprise is, it seems to us, the best possible 
witness of the Church's general attitude to ward astron- 
omy in the sixteenth century. If fifty years after 
Gregory's reform the Church saw fit to condemn the 



176 Reform of the Calendar. 

great Galileo, it must have been for some other reason 
than aversion to astronomy and hostility to the ad- 
vance of science. 

Galileo was already alive, be it known, and had 
even reached his eighteenth year, at the time that 
the Roman Pontiff proclaimed the reconstruction of 
the calendar. Whether in Galileo's maturer years the 
Church's mind respecting science had become mate- 
rially altered, is a question that awaits discussion at 
our hands in a later chapter. 

RECEPTION OF THE NEW CALENDAR. 

Meantime, as an additional preface and help to a 
proper understanding of the Galileo case, we may well 
carry a little farther the history of the calendar. The 
story of the Pope's reform of the calendar is not com- 
plete till there is added an account of the manner in 
which it was received by the different countries of 
Europe. Knowing as we do now that the reform was 
a distinct advance in astronomical practice, we are 
curious to learn if it was immediately recognized as 
such and universally adopted. All astronomers of 
today agree in commending the action of the Holy 
Father as agreeable to the demands of scientific truth. 
But it would be a hasty inference to conclude that 
such commendation was iiniversally bestowed on the 
Holy Father's act from the beginning. 

The truth of the matter is that the Protestant 
States were very reluctant to accept the proposed 
reform. Germany in its non-Catholic sections held 
out against the reconstructed calendar for over a 
hundred years, England for almost two hundred, 



Reform of the Calendar. 177 

while in Russia the opposition has lasted down to the 
present day. A somewhat detailed consideration of 
these facts may prove instructive. 

Attitude of Various Governments. Of Catholic 
countries it is almost superfluous to speak in this 
connection. It goes without saying that they adopted 
the revised calendar at once, for their spirit was one 
of perfect submission to the decrees of Rome. In 
Germany and Denmark, on the contrary, the new 
calendar had to fight its way into favor against de- 
termined opposition, and was not finally adopted till 
the year 1700. 

Long before this date its case had been fully and 
fairly presented before the legislative assemblies of 
these two Protestant countries. We read, for exam- 
ple, that Kepler, the eminent astronomer, himself a 
Protestant, appeared before the German Diet in 1613, 
pleading the cause of the Gregorian reform. He was 
fully persuaded of its wisdom and its truth. He 
believed in it as firmly as in the Copemican system 
of the heavens. But though he advocated it with all 
the authority of his office as Astronomer Royal of the 
Austrian Empire and with the wealth of argument 
that only a Kepler could muster, his plea was rejected 
and the Gregorian calendar remained excluded from 
this Protestant realm till the close of the century. 

England's Delay. A similar fate awaited the new 
calendar in England. Owing to anti-papal prejudices, 
coupled perhaps with alleged arguments of inconve- 
nience, the English Parliament midst its many vicissi- 
tudes refused to ratify the suggested change of dates 
and system until the year ] 752. In the meantime 
there had occurred the scholarly ages of Elizabeth 



178 Reform of the Calendar. 

and Anne, with the troubled period of Cromwell and 
the Charleses intervening. The country had admitted 
many changes of political system and dynasty, but 
had remained obdurate in its opposition to the 
Gregorian code. 

Moreover, before the final acceptance, England 
had seen arise within its borders a brilliant group of 
world-famed astronomers, a Newton, a Flamsteed, and 
a Halley. It is fair to suppose that these scientists 
appreciated the worth of the papal reform and lifted 
up their voices in its behalf, but popular prejudice, 
as the history manifestly records, retarded till after 
their deaths the much-desired ratification. 

Finally it would surprise us, were we not already 
acquainted with the fact, to learn that in Russia and 
the so-called Greek Churches of the East, the Julian 
calendar is followed to this day, with the result that 
their year now lags twelve days behind that of Western 
Europe.* 

Significance of the History. We should be loath to 
emphasize these admitted facts of history, had not so 
much been made of the Church's conduct towards 
Galileo by an army of anti-Catholic historians. 
Both sets of facts ought best perhaps to be allowed to 
rest in peace, as unfortunate exemplifications of human 
infirmity. But since the Galileo case has been 
exploited far and wide, and will doubtless continue 
an object of discussion indefinitely into the future, 
we feel constrained to lay stress on what appears to us 
a quite parallel case, in which governments other than 
the papal were the offenders. 

* Recent advices tell us that Russia has decided to adopt 
the Gregorian Calendar in 1912. 



Reform of the Calendar. 179 

In the matter of the Gregorian calendar there is 
question, not of an astronomical speculation or theory, 
but of an established scientific truth. A first refusal 
to embrace it might fairly be attributed to caution. 
For conservatism will always halt before radical and 
revolutionary changes. But in the case at issue 
the refusal persists, lasting for one, two, or three 
centuries, in one or another country. They that 
persevere in their opposition are responsible govern- 
ments, as authoritative with their subjects as the 
Roman Curia is authoritative over all Catholics. 

The point of permanence is made to forestall the 
charge that will surely be registered against Rome 
that the Catholic Church persisted in her opposition 
to Galileo's doctrine, allowing the condemnation of 
Copemicanism to remain technically on her books for 
almost two hundred years. The English Govern- 
ment's condemnation of Gregorianism, for such it 
may truthfully be styled, lasted well-nigh as long, 
from 1582 till 1752. 

Finally, the motive underlying the rejection of 
Gregorianism by the Protestant States was chiefly 
sectarian prejudice and intolerance. We dislike to 
use terms that connote one of the most unpleasant 
phases of human temper and action. But softer 
words would hardly express the reality. Rome's 
motive, on the other hand, in instituting proceedings 
against Galileo, was the defence of the Holy Scriptures 
whose authority she thought, perhaps mistakenly, to 
have been impugned. 

Parallels in History. A fuller understanding of this 
parallel will appear when the Galileo incident shall 
have been reviewed. But on the basis of what has 



180 Reform of the Calendar. 

been cited above, we submit that there is a parallel, 
which ought not to be disregarded. As far as our 
knowledge reaches, it is a parallel that has never been 
properly accentuated in any one of the numerous 
discussions of the famous trial and condemnation of 
Galileo. 

As a mere statement of fact, we plead that as serious 
charges of opposition to the advance of science might 
be made against the non-Catholic courts of Europe 
as have so repeatedly been preferred against the 
Roman Curia touching the case of Galileo. We sub- 
mit this, however, without sympathetic endorsement 
of the charges on either side. We offer it merely as a 
fair rejoinder. 



CHAPTER XVIII. 
GALILEO AS A PHYSICIST. 

The name of Galileo has become familiar to all 
students of history because of his condemnation by 
the authorities of the church. Putting aside for the 
moment all consideration of Galileo's conflict with 
the church authorities, a study of Galileo as a physicist 
and of the part he played in the development of man's 
knowledge of the physical world becomes a matter 
of interest. 

To appreciate the importance of his achievements, 
something of the earlier history of physical science 
should be known, and in particular how the world had 
for almost two thousand years been committed to the 
physical system of Aristotle, the ancient Greek 
philosopher. All through the Middle Ages, scholars, 
both Christian and Arabian, looked upon Aristotle 
as an unquestionable authority, hailed him as their 
master, and drew from his works their entire system 
of physical science. 

This was not unnatural in view of the fact that 
Aristotle was the greatest genius of antiquity. He 
is still acknowledged as the first great naturalist in the 
order of time, and is regarded as one of the greatest 
philosophers of all times. It is no disparagement 
to his general talent to say that his physics, both of the 
heavens and the earth, was faulty and incomplete. 

181 



182 Galileo as a Physicist. 

That he was interested in physics, his many works 
on that subject are evident proof, but his assertion 
of facts seems often to have been incorrect and his 
solution of physical problems is today unsatisfying. 
He insisted too much on the method of deduction, 
employing too little the method of induction and 
experience. 

The Middle Ages Followed Aristotle. The Middle 
Ages, engrossed in other and, it may be claimed, better 
and more important things, did not take time to cor- 
rect the errors and revise the methods of Aristotle. 
And so through natural causes, there came down to 
the sixteenth century a heritage of physical science 
that must be described as meagre and inexact. To 
connect the errors and revise the methods of Aristotle 
there was need of a genius who should make a new 
study of nature's laws. 

It was the achievement of Galileo to bring about the 
renaissance of physical science and lay the foundation 
for the wonderful advances in physical knowledge 
that have signalized the last three hundred years. At 
Pisa, Italy, in February, 1564, was born Galileo 
Galilei, the father and founder of modem physics. 
His father was not wealthy, and, burdened with a 
large family, was unable to provide expensive in- 
structors for his children, yet, becoming every day 
more sensible of his eldest son's talent, he decided, 
at whatever cost, to give him the advantage of a 
university education. Accordingly young Galileo, in 
his eighteenth year, was entered at the University 
of Pisa, to prepare for the medical profession. 

First Signs of Future Greatness. It was at this 
time that he made the first and not the least inter- 



Galileo as a Physicist. 183 

esting of his discoveries. While praying one day in 
the Baptistery of Pisa, his attention was drawn to the 
great sanctuary lanxp, which, after being lighted, 
had been left swinging. It struck him as a significant 
fact that whether the arc through which the lamp 
oscillated was great or small, the time occupied in 
each swing was apparently the same. He proceeded 
to compare its oscillations with his pulse beats and he 
found that the time of each vibration remained the 
same, even after the motion had greatly dimin- 
ished. Thus was discovered the first law of the 
pendulum. 

He first applied this law to the construction of a 
pulse gauge which aided physicians in counting the 
pulse beats of their patients. In later years Galileo 
improved this invention and prepared the way for the 
modem pendulum clock which was invented by 
Christian Huyghens in 1668, just sixteen years after 
Galileo's death. The pendulum has since been put 
to other uses besides that familiar one in the pendulum 
clock, and today its study occupies a fairly large chap- 
ter in manuals of physics. It is not to be forgotten 
that Galileo was the first to direct the world's atten- 
tion to it, the first to announce its laws and suggest 
its use. 

Aptitude for Mathematics. It was during his 
academic career that his talent for mathematics first 
became manifest and induced him to abandon his 
medical books for the more congenial problems of 
Euclid and the fascinating treatises of Archimedes 
and other ancient geometers. He even improved 
upon the methods of Archimedes, the greatest of the 
Greek physicists, and invented an instrument which 



184 Galileo as a Physicist. 

in its uses was very similar to our present hydrostatic 
balance. This invention, joined to his previous 
discovery of the laws of the pendulum, secured for 
him a widespread reputation and the intimate 
friendship of many of the distinguished personages 
of Italy. It is not surprising, therefore, to see the 
chair of mathematics at the University of Pisa con- 
ferred on him, though he had scarcely attained his 
twenty-fifth year. 

Flattered by this distinction, the young professor 
left nothing undone that was calculated to justify 
the preference that had been shown him. Conceiving 
that the basis of all physical study rested on the 
laws of motion, he endeavored to establish these 
more firmly, not by hypothetical reasoning, as was 
the custom of the time, but by real experiments. 
In this he incurred the enmity of his fellow philos- 
ophers and scientists, who were loath to depart from 
the ancient and time-honored methods of Aristotle. 

In his attempts to formulate the laws of motion he 
refused to accept Aristotle's theory of falling bodies, 
which claimed that the velocity of a falling body 
depends on its weight, or, in other words, the heavier 
a body is, the less time will it require to fall from a 
certain height to the earth. 

The Experiment at Tower of Pisa. Having satisfied 
himself of the falsity of this belief, which had received 
the sanction of the learned for nearly two thousand 
years, he resolved to vindicate his position in a public 
demonstration. Yonder leaning tower of Pisa, which 
seemed to have bent over purposely to facilitate the 
experiment, offered an ideal spot for the demonstration. 
One morning, before an immense concourse of people, 



Galileo as a Physicist. 185 

including the assembled university, Galileo ascended 
the tower and let drop from its top simultaneously 
two shots weighing one and one hundred pounds 
respectively. According to the current belief the 
heavier shot should reach the ground first, but such 
was found not to be the case. The multitude of 
spectators, to their great amazement, saw the two 
balls start together, fall side by side, and reach the 
ground at the same moment. 

Thus the first great step was taken in the overthrow 
of that imperfect system which had impeded the 
development of physics and other natural sciences 
for over nineteen centuries. On the basis of these 
and similar experiments, Galileo was enabled to 
announce the laws of falling bodies — a subject which 
now forms one of the basic chapters in the science 
of mechanics. 

Becomes Professor in Padua. But Galileo was in 
advance of his time, at least at the University of 
Pisa, and in 1592, because of the novel and unwel- 
come character of his teachings, he was obliged to 
resign his chair after only three years of tenure. 
Undaunted by this reverse of fortune, he went to 
Florence, where he met some friends who were in- 
fluential enough to secure his appointment to the 
chair of mathematics at the University of Padua. 
Not all the universities were hostile to the new teaching, 
for at Padua he enjoyed perfect freedom. All the 
time he could spare from his professional duties he 
employed in private study and in making incessant 
experiments. Chief among his inventions at this 
time was his air thermometer. The original idea of 
this instrument belongs to Hero, the Greek mathema- 



186 Galileo as a Physicist. 

tician, but Galileo was the first to construct it in 
practical form. 

Galileo's genius, now ripening into maturity, began 
to startle the world with its revelations in physical 
science. He was the first to show that the path of 
a projectile is a parabola. Previously it had been 
believed that a cannon ball or missile moves forward 
first in a straight line and then drops vertically to 
the ground. The phenomenon he explained by stat- 
ing that any body projected into space is constantly 
being acted upon by gravity and thereby gradually 
attracted to the earth. 

Discovers New Principles. His famous principle of 
the parallelogram of forces, which practically started 
anew the study of dynamics, was discovered at this 
time, but its importance and significance were almost 
forgotten in the excitement and enthusiasm aroused 
by the greater discoveries soon after to follow. 
Early in the year 1609 a report was circulated that 
a spectacle-maker of Middleburg in Holland had 
constructed an instrument by which distant objects 
were made to seem nearer. Galileo on hearing this 
puzzled his brain as to the possibility of constructing 
such an instrument. 

Concluding that this phenomenon had its basis in 
the theory of perspective, he began to experiment 
with spherical glasses, and his first telescope consisted 
merely of a leaden tube with two lenses, one plano- 
concave and the other plano-convex. It made objects 
appear three times nearer. Enthused by this success, 
he spared neither time nor labor in his efforts to im- 
prove his invention, and he finally secured a telescope 
that would make objects appear thirty times nearer. 



Galileo as a Physicist. 187 

If the invention of the telescope does not strictly 
belong to Galileo in the order of time, since, as we 
have seen, a Dutch spectacle-maker accidentally 
discovered the principle while working with lenses, 
it remained for the Italian genius to perfect it and to 
divine its real value. 

First to Use Telescope on Heavens. Galileo was 
the first to turn the telescope upon the heavens, and 
he observed there what no mortal eye had seen before : 
the craters and deep valleys of the moon, the various 
phases of Venus, the four satellites of Jupiter, the 
separate stars of the milky way, the nebulae, and the 
whole heavens dotted with myriads of stars of which 
man had never dreamed. So widespread was the 
fame of Galileo after this discovery that he was 
beseiged with orders for telescopes from all parts of 
Europe. As a recompense for his ingenuity, his com- 
mission as professor was prolonged for life with a 
salary triple that which he had previously received. 

The remaining years till his death in 1642 are less 
pleasing to contemplate, for it was then that he be- 
came embroiled in controversies with other scientists 
and with the church authorities. Moreover, little 
in the way of new invention occurred to make this 
period memorable. That he was not entirely idle, 
however, is proved by the fact that in 1637, only six 
years before his death, his telescope revealed to him 
one other astronomical fact of no little importance, 
the moon's libration, as it is technically called. 

Summary of Galileo's Achievements. Summing up 
Galileo's achievements, we may say that he did much 
for physics both theoretical and applied. By his 
discovery of the laws of falling bodies and of the prin- 



188 Galileo as a Physicist. 

ciple of the parallelogram of forces, and by his 
discussion of centrifugal force, he laid the foundation 
of modem dynamics. To the practical side of his 
science he also contributed by his invention of time- 
keeping devices and the construction of thermometers, 
and by his reconstruction of the telescope. More- 
over, he so stimulated research and scholarship that 
there followed in his wake a long line of great phys- 
icists, culminating in Sir Isaac Newton, and within 
less than a century from his death mechanics was 
practically a completed science. 

We ought not to obscure the fact that Galileo had 
his limitations. His inventions were crude and had to 
be perfected later. What he started, others completed. 
Again, his reasoning in favor of the Copemican system 
was not always satisfactory. But these limitations 
were natural, for Galileo was in reality a pioneer, and as 
such deserves the highest admiration, and will ever be 
regarded as the founder of experimental science and 
one of the world's greatest physicists. 



CHAPTER XIX. 
THE CONDEMNATION OF GALILEO. 

The case of Galileo has been used now for two 
centuries as a stock argument against the teaching 
authority of the Catholic Church. It has been alleged 
not merely that the Roman congregation was guilty 
of a mis judgment in condemning Galileo, to which 
Catholic writers have long since agreed, but that she 
thereby proved herself adverse to the progress of 
science and forfeited her claim to doctrinal infallibility. 
Galileo himself has been pictured as the victim of 
injustice, a martyr for science, tortured, imprisoned, 
and otherwise made to suffer for his opinions. 

We shall not attempt to exonerate completely the 
tribunals that were involved. But we hold it right 
to demand of all interested that they examine the 
facts fairly and exercise that justice of judgment 
which, it is complained, Galileo did not receive. 
Otherwise their judgment is as reprehensible as that 
of the Roman tribunals taken at its worst. To be 
false to historical truth is as blameworthy as to be 
hostile to science. 

An Estimate of Tribunals. Galileo was an illustrious 
scientist, the founder of modem physics and of de- 
scriptive astronomy. The fame of his genius has given 
to his trial an importance it would not otherwise have 

189 



190 The Condemnation of Galileo. 

had, and has compelled the sympathy of subsequent 
generations. Had he been less famous a scientist, the 
incident of his condemnation might almost have 
fallen into oblivion. 

Not one in a thousand of those who sympathize 
with Galileo is aware that in precisely the same 
epoch, in the year 1624, three scientists or philosophers 
were condemned by the Sorbonne of Paris for anti- 
Aristotelian views in almost the same terms as Galileo, 
were banished b}^ the French Parliament, and they 
and all others forbidden to hold or teach such opin- 
ions under penalty of death. 

This incident is lost to view in the greater glow 
of the celebrated trial at Rome. It may be usefully 
recalled as illustrative of the spirit and temper of the 
times. Faulty as was the action of the French 
University and Parliament, the question may well be 
asked if they thereby proved themselves deliberately 
hostile to the advance of science. Would it not be 
truer to say that, though mistaken, they had followed 
their best lights ? Who, moreover, insults the memory 
of the Sorbonne and Parliament by perpetuating the 
memory of these facts to their discredit? Or who 
refuses them respect because of their mistaken 
judgment and unjust sentence? 

Though Galileo was a greater scientist than the 
three condemned in France, and though the Church 
is greater than the Sorbonne or the French Parliament, 
the principles for judging the two cases remain essen- 
tially the same. Great as was Galileo, the tribunals 
of the Church felt in the final issue that they could be 
no respecters of persons. Reluctantly but con- 
scientiously, they felt called upon to censure a man 



The Condemnation of Galileo. 191 

even of his fame. The greatness of the accused un- 
doubtedly operated in his favor, as the entire history 
proves, but could not finally save him. His very 
eminence precludes the probability that the tribunals 
acted from base or unworthy motives. To attribute 
such to Gallieo's judges is as unwarranted as to impute 
base designs to a civil court from whose unjust action 
an innocent man is unfortunately made to suffer. 

We insist upon these considerations that proper 
allowance be made for the action of what was after 
all a human tribunal. Entitled to the highest re- 
spect, the Congregations of the Inquisition and Index 
are not, however, the infallible teaching Church. 
Infallibility is a unique prerogative granted only to the 
Pope as sovereign teacher in matters of faith and mor- 
als. The Congregations are commissions or tribunals, 
discharging most important functions for the security 
of faith and morals, but not altogether free from the 
possibility of issuing some decisions that shall after- 
wards be reversed. To their acts, human rather than 
divine standards should be applied. 

The Two Condemnations. By such tribunals 
Galileo was twice condemned, first in February, 1616, 
and later in June, 1633. He was condemned in each 
case because of his adhesion to the Copemican 
system of astronomy. It would be more exact to 
state that in 1616 the Copemican theory was con- 
demned rather than the man Galileo; and that in 
1633 Galileo was sentenced partly for holding the 
condemned doctrine and partly for disobedience to a 
promise exacted from him by the Church. 



192 The Condemnation of Galileo. 



THE FIRST CONDEMNATION. 

In the first of the two years mentioned, there was 
question of the astronomical system founded by 
Copernicus, a Catholic ecclesiastic. For years this 
system had remained immune from censure, and would 
have continued to do so had not scriptural considera- 
tions been introduced. Physical science, as such, 
was outside the Church's province, but brought into 
relation with the Scriptures, of which the Church 
was the lawful interpreter, it awakened her interest. 
A letter of Galileo to his pupil Castelli,a Benedictine 
monk, attempting to reconcile Scripture with the 
Copemican system, inaugurated the conflict. This 
letter, written December 21, 1613, was reported to the 
Congregation of the Index. The delay till February, 
1616, proves that action was not taken in undue 
haste. 

What was the exact decision of 1616, and from 
what body or bodies did it emanate? It is true that a 
committee of theologians appointed by the Inquisition 
pronounced the Copernican doctrine "absurd and 
formally heretical." But this report was not the 
decision of any Congregation; it merely formed the 
doctrinal basis of the practical action now to be taken. 

Indeed, there was no formal doctrinal pronounce- 
ment made in 1616, nor was the Inquisition, as such, 
directly involved. For the moment the sentences 
passed were purely disciplinary and practical. Galileo 
was asked by Cardinal Bellarmine to promise not to 
hold, defend, or teach the Copemican doctrine. He 
gave promise in writing and apparently with complete 
willingness. He was not asked to abjure nor did he 



The Condemnation of Galileo. 193 

suffer any penance or other punishment. A fort- 
night later he had an entirely friendly audience of 
three-quarters of an hour with Pope Paul V, and a 
few months after left Rome with good reputation and 
with no charge resting upon him. The martyrdom 
of Galileo, therefore, did not begin as early as the 
year 1616. 

The Interdiction of Books. Less mild than the 
sentence passed on Galileo was the decree of the 
Congregation of the Index. Believing and even 
asserting the Copernican system to be "false and 
contrary to the Scriptures," the Congregation took 
up for censure certain books inculcating it. Even 
now no writing of Galileo's was censured, out of 
deference for the great astronomer. The only book 
prohibited outright and by name was one recently 
published by the Carmelite priest Toscarini, which 
aimed professedly to prove that the Copernican 
system is in agreement with the Sacred Scriptures. 
With it were prohibited in general terms all other 
books of the same tenor. 

Only conditional censure was applied to Copernican 
books that avoided the Scriptural argument. Thus 
the original work of Copernicus himself, as well as one 
other named, was merely "suspended until it should be 
corrected." Four years later, the desired corrections 
were indicated, eight in number, qualifying the 
Copernican doctrine as an hypothesis instead of being 
an established truth. 

It was clearly the mind of the Congregation, and 
this was never repealed in later utterances, that the 
opinion might be broached as an hypothesis and as a 
subject for discussion. Its harmony with the Scrip- 



194 The Condemnation of Galileo. 

tures might not, however, be defended. Perhaps 
there was inconsistency here, but the distinction was 
sincerely if illogically made. With a scientific 
system as such the Congregation did not care to 
meddle, but it asserted its right to decide on the cor- 
rect interpretation of the Scriptures. 

This decree of the Index will impress us differently 
according as we view it in its genesis or in its 
consequences. In its origin the decree was not 
unnatural nor, we may say, unwarranted. Coperni- 
canism was still but a theory, as astronomers now 
agree. Most scientists of the time were against 
it. Against it were quoted certain Scriptural texts, 
then interpreted literally. The Congregation, there- 
fore, thought to follow the best science of the time, 
bothphysical and scriptural, by opposing in a measure 
the Copemican teachings. Though in error, it was 
certainly not consciously opposed to the onward march 
of Science. Indeed, it thought to allow for future 
developments by permitting the teaching of Copemi- 
canism as an hypothesis. 

The event proved, however, that the action had not 
been of the wisest. The distinction between "hypo- 
thetically possible" and "contrary to the Scriptures" 
was beyond the reach of the average mind, and 
appeared, in fact, to involve a contradiction. So 
it came to pass that the generality of men remembered 
only that the theory had been condemned as "false 
and contrary to the Scriptures." In course of time, 
two other books were placed upon the Index, Kepler's 
"Epitome of the Copemican Astronomy," in 1620 
or thereabouts, and Galileo's "Dialogue," in 1633. 
The effect of these edicts in restraining Catholics 



The Condemnation of Galileo. 195 

from embracing Copemican views, remained in full 
force for about a hundred years. The nominal pro- 
hibition of the condemned books lasted for a hundred 
years longer. 

Appreciation of the Decree. In forming a judg- 
ment of these decisions of the Congregation of the 
Index, we must remember that its action was not 
doctrinal but disciplinary. Of like character is every 
decision of this Congregation, merely regulating the 
conduct of the faithful in the matter of books and 
reading. If the effects were unfortunate for a certain 
system of science now admitted to be true, this was 
beyond both the intention of the Congregation and its 
power of foresight. Indeed, the Congregation thought 
it had made ample provision against such unhappy 
consequences by permitting the Copemican system 
to be taught as an hypothesis. It underestimated 
the effective influence of the words it had used in 
proscribing Copemicanism as "false and contrary 
to the Scriptures." 

THE SECOND CONDEMNATION. 

From these first decisions we now pass to the later 
decrees bearing on the case, those of the year 1633. 
They are more likely to arouse the sympathy of the 
reader, for they involve immediately the person and 
fortunes of the great astronomer. Whereas in the 
first pronouncement sentence had been passed upon a 
doctrine, in the second, as will be seen, the sentence 
bore directly upon an individual. 

Change of Officials. Meantime certain changes of 
officials had occurred that were not without influence 



196 The Condemnation of Galileo. 

on the ultimate result. In the year 1621 there died 
three persons of exalted rank : Pope Paul V, who had 
helped procure the first decrees though he had not 
signed them; Cosmo II , Grand Duke of Tuscany, the 
staunch friend of Galileo, his political subject; and 
Cardinal Bellarmine, who had been actively concerned 
in the first action taken, though by no means the 
"terrible opponent" that Andrew D. White describes. 

Bellarmine was a man of seventy -four when the 
first decree was issued. Schooled in the science of 
Aristotle and Ptolemy, he was not likely at his great 
age to accept what appeared to him revolutionary 
doctrines. Undoubtedly he was instrumental in 
procuring the Index decrees of 1616, for he believed 
sincerely that the Copernican opinion was "false and 
contrary to the Scriptures." But he sought no per- 
secution of Galileo. On the contrary, he defended 
him from the calumnies that were being circulated 
by giving him in May, 1616, a signed declaration. 
This declaration, to which Galileo appealed in his 
trial, was to the effect that Galileo had not been asked 
to abjure or to do penance, but had been informed 
of the decision prohibiting future defence of the 
Copernican doctrine. 

Andrew D. White's description of Bellarmine as 
"the most terrible opponent" of Galileo is one of his 
many rhetorical exaggerations. All should know 
that Bellarmine had no share in the transactions of 
1633, for his decease had occurred twelve years earlier. 
With him, however, did not die the race of ardent 
Aristotelians and Ptolemaists. 

Cosmo II was succeeded as Duke of Tuscany by his 
son, Ferdinand II, who became Galileo's most 



The Condemnation of Galileo. 197 

influential patron and friend. Pope Paul V was 
succeeded by Gregory XV, who reigned, however, 
but two years, when there came to the papal throne 
in 1623 Cardinal Barberini under the name of Urban 
VIII. Patron of art and learning and an energetic 
ruler, this prelate was destined to outlive Galileo, 
and was therefore the pontiff under whom the scientist 
was condemned and made to spend his last years in 
nominal imprisonment. 

Pope Urban VIII. The accession of Urban VIII was 
a potent factor in shaping Gallieo's conduct. The 
new Pope, when cardinal, had befriended him in a 
dozen different ways. As early as 1611 he had dis- 
played great interest in his telescopic discoveries. 
He had probably assisted in saving Galileo's person 
and his writings in 1616. A few years later he had 
written verses in his honor. To the new Pope 
Galileo dedicated a volume just finished, "The 
Assayer." The Holy Father accepted the dedica- 
tion and expressed himself as delighted with the 
work. 

He now showed his esteem for the astronomer by 
vouchsafing him six audiences in quick succession in 
1624. One topic of their conversation was the Co- 
pemican system, of whose truth, however, Galileo 
failed to convince the pontiff. The latter conferred 
on the astronomer at his departure many favors and 
presents, as well as a pension for his son. Just after, 
in June, 1624, Urban wrote to the Grand Duke of 
Tuscany, praising the learning and piety of Galileo. 
Be it remarked here that the recipient of these ponti- 
fical favors remained all his life a devout and sincere 
Catholic. 



198 The Condemnation of Galileo. 

Galileo's Blunder. The distinguished scholar, how- 
ever, presumed too far on the favor of the Sovereign 
Pontiff. Inattentive to his solemn promise of 1616, 
he re-entered the dangerous field of Copemican dis- 
cussion. He spent the next six years in composing 
a book, The Dialogue of the Two Systems, not the 
greatest of his works but the most celebrated because 
it occasioned his downfall. In it he presented both 
sides of the argument, but seemed to betray a very 
strong preference for the Copemican position. 

In 1630 he was again at Rome, seeking now an 
imprimatur for his book. The Pope again received 
him and doubled the pension of his son. The story 
of the next two years is that of Galileo's effort to gain 
official sanction for "The Dialogue." At Florence 
he succeeded wholly, at Rome only in part. When the 
work appeared, he dared to insert the imprimatur 
both of Florence and of Rome, thereby offending 
Fr. Riccardi, the examiner at Rome, a former pupil 
and devoted friend. 

The work, apparently avowing Copemican views, 
aroused excitement and even fury. The Holy Father 
was angered at this breach of confidence and of 
discipline. In September, 1632, he committed the 
volume for examination to a special commission. 
They reported that Galileo was guilty both of violating 
his personal promise and of upholding a doctrine 
condemned by the Church. 

The Trial of Galileo. The author was summoned 
to Rome. Procrastinating, he delayed answering 
the summons from October, 1632, to February, 1633. 
Let these four months be set against the subsequent 
four in which too zealous sympathizers complain that 



The Condemnation of Galileo. 199 

he was kept waiting for the final verdict. There is 
no indication that the verdict was purposely delayed 
to incomrnode the accused astronomer. 

During all this period, moreover, the defendant 
was comfortably quartered, not kept in the dungeons 
of the Inquisition, as exaggeration would have it. 
Most of the time was passed in the house of Niccolini, 
the Tuscan ambassador, his staunchest supporter at 
Rome. Only twenty-two days were spent in the 
palace of the Inquisition, and these not in a prison, 
but in a suite of three fine rooms, with the attendance 
of Galileo's own body servant, and with frequent visits 
from the Tuscan ambassador and ambassadress. 

Four interrogatories or hearings were given the 
accused by the Inquisition from April 12 to June 21. 
Galileo's defence was a denial of the charges. He 
protested that he had not broken his engagement, 
and appealed for the terms of that engagement to 
Bellarmine's Declaration. He claimed that in his 
Dialogue he had not designedly shown preference 
for the Copernican system, but had meant to present 
both systems with equal force. Finally, at the last 
hearing he reiterated again and again, even under 
threat of torture, that interiorly he did not hold to the 
Copernican system, but since the decree of 1616 had 
always believed the Ptolemaic system to be true. 

The Sentencing of Galileo. Notwithstanding his 
disclaimers, the Inquisition found him guilty of the 
twofold charge, of having broken his agreement and 
of having taught Copemicanism, a forbidden doctrine. 
The climax came with the pronouncement of the 
sentence June 22, 1633. He was declared "vehe- 
mently suspected of heresy," was ordered to abjure 



200 The Condemnation of Galileo. 

the Copemican doctrine, and was condemned to im- 
prisonment and also to a penance, the recitation of the 
Penitential Psalms once a week for three years. The 
decree of the Inquisition, very solemn in its form, but 
in substance just as given above, was signed by seven 
of the ten cardinals composing the Congregation. 

The same day Galileo was made on bended knees 
to pronounce and sign his abjuration. He was made 
to say that he "abjured, cursed and abhorred" the 
doctrine that the sun is stationary and that the earth 
revolves about it. The solemnity of the form of 
abjuration is discounted somewhat when we learn that 
it belonged to the legal phraseology of the time. 
But the dramatic pathos of the incident remains. 
An aged scientist on bended knees forswearing a belief 
to which all his scientific studies inclined him, in 
presence of the supreme court of the Church, is a 
spectacle that has never ceased to elicit sympathy. 

Later on, romancers added other details of their 
own invention to heighten the spectacular character 
of the episode. They fancied that the culprit had 
been subject to actual physical torture, which is 
contrary to all the evidence that we possess. They 
retailed with delight the story that on rising from his 
knees Galileo had protested defiantly, "And yet it 
moves. " This interesting story is, however, a fabrica- 
tion of comparatively recent date, traceable no farther 
back than 1761, more than a centur}^ and a quarter 
after the event in question. 

Judgment of the Case. Such are the bare facts in 
the case, given without coloring. The impression 
they leave will vary with the temper of mind of the 
individual reader. It will be sympathy in one man. 



The Condemnation of Galileo. 201 

indignation in another, and perhaps cold calculating 
indifference in a third. 

We have no intention of attempting to justify 
completely the decision of the court. The underlying 
basis of the decree of 1633 was a doctrinal mistake. 
Nevertheless we hold it fair to submit as extenuating 
circumstances that Galileo had been technically guilty 
of legal faults, and that the court's decision in 1633 was 
rendered according to the law actually in force. 

SINCERITY OF GALILEO. 

In our minds as we have been perusing the history, 
there has arisen the further question, what were 
Galileo's interior convictions respecting Copemicanism 
at the moment of his abjuration? Was he coerced to 
perjure himself, or was he perfectly sincere? 

The question is worthy of examination. For the 
renunciation of the Copernican system by Galileo is 
generally esteemed the most dishonorable episode in 
the entire history. It is commonly supposed, even 
by writers of authority, that at the moment of his 
abjuration Galileo was fully convinced of the truth 
of Copemicanism, and therefore committed perjury. 

Galileo's Inward Belief. There is a minority 
opinion, however, of utmost interest in its bearing 
on the case, that the astronomer's act of abjuration 
was absolutely truthful and sincere. The reasons 
for this opinion are not without weight. In seeking 
to penetrate Galileo's innermost thoughts, we must 
evidently adopt the standpoint of the seventeenth cen- 
tury, not that of the twentieth. We must, in addition, 
consider the general character of Galileo's studies. 



202 The Condemnation of Galileo. 

Copemicanism was, at the time, a novel doctrine, 
repudiated by the vast majority of the learned, 
theologians and scientists alike. Their opposition 
could scarcely have been without some effect on the 
mind of the Florentine astronomer. In physics and 
mathematics, indeed, which were his specialty, there 
is little doubt that his opinions were proof against 
all such adverse criticism. But in astronomy the 
case was somewhat different. The proofs of the Co- 
pemican theory were incapable of being tested in 
the laboratory. The arguments in its favor were not 
as yet above reproach. 

Noteworthy is it also that Galileo did not become 
a public advocate of Copemicanism till comparatively 
late in life. It was his telescopic discoveries of the 
years 1609 and 1610 that won him to the cause. On 
the basis of the facts they supplied, he wrote his first 
book in defence of the novel doctrine in 1613, when he 
was almost fifty years of age. Even then, with his 
fine powers of logic, he must have discerned that the 
arguments were not conclusive but only probable. 
On the scientific side, then, while he leaned strongly 
to the Copemican system, he could not establish it 
with certitude as he could, for example, his laws of 
falling bodies. 

His Respect for Superiors. Combine with this now 
the fact of Galileo's profound respect for his ecclesias- 
tical superiors. He wrote in 1614 that he would rather 
have an eye plucked out than resist his superiors by 
upholding against them the opinion of Copernicus. 
In the light of this statement, may we not believe 
that the mere teaching of the Church authorities 
sufficed at times to outweigh, in his estimation, even 



The Condemnation of Galileo. 203 

the scientific arguments ? Facts show that he sought 
in every way not to offend against the commands of 
the Roman tribunals. It is only when we remember 
how true a Catholic Galileo was, that we can measure 
the depth of the impression made upon him by the 
Church's official decisions. 

On all these grounds we are inclined to believe that 
Galileo did not continue unremittingly attached to 
the Copemican system, but wavered from this side 
to that, swayed now by scientific reasons, now by 
the counsel and authority of his superiors. That 
a great scientist may thus waver in his views is proved 
by the parallel case of Buff on, the French naturalist 
of the eighteenth century, at first an anti-evolutionist, 
later an evolutionist, and in the end adopting a com- 
promise opinion. 

His Sincerity. If we can suppose such fluctua- 
tions in the mind of Galileo, then we can understand 
perfectly all his asseverations before the court of the 
Inquisition. He could say with utmost truthfulness 
that at that moment he repudiated the Copemican 
theory, bidden to do so by those for whose doctrinal 
decisions he had the highest respect. He could even 
aver conscientiously, after a vain endeavor to dis- 
entangle his conflicting emotions and opinions of the 
past, that from the time of the decree of 1616 he had 
always yielded his interior assent to that decision. 

By such a judgment as we have ventured to suggest, 
the veracity of Galileo is rescued and made secure. 
Standing before the Inquisition, he is no perjurer, 
even technically or as the result of an extortion he 
could not resist, but he is still truthful in utterance 
and noble in deportment, without pride of mind 



204 The Condemnation of Galileo. 

submitting his judgment to that of his superiors. 
Moreover, we thereby save the honor and dignity of 
the whole occasion. Neither GaHleo nor his judges 
will appear to us hereafter as conscious hypocrites. 
The officers of the Inquisition, though convinced of 
his former guilt, believed him now sincere. Other- 
wise we cannot explain their final expression of 
approval, "Thou hast answered as a Catholic." 

CHARACTER OF HIS IMPRISONMENT. 

Galileo's Last Years. We now come to the final 
period of Galileo's life. In our analysis of it, we shall 
cling to the purpose we have maintained from the 
beginning, to consider only the official acts of the 
Church authorities, not the attacks and prejudices 
of private individuals. The acts of his personal 
enemies and antagonists may have been dictated by 
passion and malevolence. Not so the official decisions 
of the Roman Congregations. Their sentence, how- 
ever fallible, rested on what the members conceived 
to be the demands of truth and justice. 

We have stated that the Inquisition condemned 
Galileo to the punishment of imprisonment. But 
immediately a higher authority, the Holy Father, 
intervened, commuting the sentence into such a form 
that the imprisonment became only nominal. It is 
doubtful if Galileo spent a single day in the dungeons 
of the Inquisition. He was permitted to go at once 
to the house of his friend, the Tuscan ambassador. 

After a fortnight, the place of his seclusion was 
changed by order of the Pope to the palace of the 
Archbishop of Siena, one of his most loyal friends 



The Condemnation of Galileo. 205 

and admirers. In Siena, whose climate was more 
salubrious than that of Rome, he tarried some six 
months till about the close of the year 1633. But 
he panted for Florence and Tuscany, his native realm 
and the scene of his greatest triumphs. Permission 
was soon granted him to repair to his own villa at 
Arcetri near Florence, where he was destined to spend 
most of the remainder of his life. 

Character of His Punishment. It is true that he was 
still held to a determined place of residence, obliged 
to live in comparative seclusion and forbidden perfect 
liberty of movement. His heart's desire to enter 
Florence was not gratified till 1638, when he had 
become completely blind and needed to be nearer the 
expert oculists of the city. Moreover, whether at 
Arcetri or Florence, he was not permitted to invite 
his friends, or to receive them in such numbers as 
might appear to constitute a class assembled for 
instruction. But, barring these restrictions, his 
liberty was well-nigh complete. 

With him lived his son Vincenzo, and in his decli- 
ning years several of his favorite disciples, Fr. Castelli, 
Viviani, and Torricelli. Not far away there dwelt 
in a convent his two daughters, Franciscan nuns, 
whom he could visit at will. One of these daughters 
Sister Maria Celeste, his dearest consolation, took 
upon herself his penance of prayer, but did not live 
to complete it. Nor was his companionship limited 
to those just mentioned. He was quite free to receive 
his relatives and friends, and even admiring strangers 
like Milton, the English poet, who visited him at 
Arcetri in 1637. His seclusion from the world, there- 
fore, was far from being absolute. 



206 The Condemnation of Galileo. 

Intellectual Activity. It is commonly supposed 
by men of superficial knowledge of the case, that 
Galileo's life was one of extreme sadness after the 
decree of the Inquisition had been pronounced. There 
is only a fragment of truth in this belief. Galileo 
must indeed have felt, at times most keenly, the dis- 
grace of his condemnation, all the more that he was 
so devoted a child of the Church. But, whatever his 
feelings, there never escaped from his pen or lips, 
as far as we know, a single word of protestation 
that Rome had acted cruelly or that he had been the 
victim of injustice. In a very few instances he wrote 
with sadness in private letters of the unjust attacks 
made by his enemies and antagonists. But these 
animadversions are rare in his extant writings, and 
were never once directed against the tribunals or 
officials of the Church. 

Finally, we should have expected to learn that after 
the condemnation Galileo was a crushed man and that 
his intellectual activity must then have practically 
ceased. So far from the truth is this that his greatest 
literary work and monument was composed in the 
period we are now considering. His observational 
and mental activity remained as of yore. In 1637 he 
discovered with the telescope the libration of the 
Moon. In the following year he brought out his 
greatest book, the Dialogue of the New Sciences, in 
which, as he himself describes it, he summed up the 
best results of his lifework in science. 

To the last he was busy instructing his little knot 
of favorite disciples, suggesting the plan of the 
pendulum clock when his end was almost at hand. 
His scientific career during his last nine years proves 



The Condemnation of Galileo. 207 

abundantly that his mind was calm and tranquil, 
and that he had accepted with admirable resignation 
the adverse decisions of the court of Rome. 

Death and Burial. He died in February, 1642, 
fortified with the last sacraments of the Church and 
with the special benediction of Pope Urban VIII. His 
remains were at first interred in an obscure chapel of 
the Church of Santa Croce at Florence. Enthusiastic 
friends would fain have raised a monument to his 
memory, but this the Pope forbade, deeming it im- 
prudent thus to honor a man who had been officially 
condemned. 

Later, more tolerant counsels prevailed, his body 
was moved to a nobler resting place in the Church of 
Santa Croce, and above the sepulchre was reared with 
ecclesiastical approval a monument in stone. In- 
scribed on its front we read a glowing tribute to the 
memory of the distinguished scientist, "Galileo 
Galilei, Greatest Restorer of Geometry , Astronomy, 
Philosophy, Comparable to No Man of His Age." 



CHAPTER XX. 
RECENT CATHOLIC ASTRONOMERS. 

In the progress that astronomy has made since the 
time of GaHleo, Cathohcs have had an honorable 
share. The extent of their achievements is hard even 
for the scholar to determine. For nearly all our 
ordinary books of reference dealing with the history 
of astronomy, neglect almost entirely the religious 
beliefs of the world's chief scientists. Not the least 
service of the Catholic Encyclopedia will be to make 
known to English readers the goodly list of Catholics 
who have done notable work in astronomy and in other 
departments of learning. Uncertainty about this or 
that scientist's religious profession will disappear in 
the light of its authoritative and ably-written articles. 

After Galileo. Already we know enough to affirm 
that the condemnation of Galileo did not diminish 
or discourage the study of the astral science by the 
children of the Church. The great Florentine had 
pointed the way. He had discovered a new inlet that 
led into a previously unknown continent. Into this 
channel so rich in promise there entered a multitude 
of navigators of every nationality and of many re- 
ligious persuasions. The different nationalities of 
the quartette of astronomers pre-eminent in the 
seventeenth century give an excellent example of the 
cosmopolitan character of the science. For Galileo 

208 



Recent Catholic Astronomers. 209 

himself was an Italian, Kepler a German, Huyghens 
a Hollander, and Newton an Englishman. 

In the second and lower ranks was at work a small 
army of investigators, among whom might be found 
a large number representing the Latin races and the 
Catholic faith. Vacandard's article on the con- 
demnation of Galileo enumerates over a dozen Italians 
who in this period contributed notably to the advance 
of mathematics and astronomy. Almost half of those 
named belonged to the Society of Jesus, an order 
which from Fr. Clavius down to the present moment 
has never failed to produce a respectable quota of 
industrious and successful laborers in this field. In 
general it is to be noted that Vacandard's list includes 
only those who studied and taught under the direct 
supervision of the Church, at the papal universities 
of Rome and Bologna. 

CASSINI. 

Domenico Cassini. Conspicuous in the list is one 
but little known to English readers, but so eminent 
in his profession as to deserve mention just after the 
illustrious quartette named above. We single him 
out for special study advisedly. Better is it to con- 
template in leisurely fashion one noble figure such as 
his than to heap together a long list of foreign-sound- 
ing names that would be forgotten as soon as read. 

The name of Cassini deserves not to be forgotten, 
nor will it be so long as any are found interested in the 
peaceful triumphs of the past. It is a name that 
continued to adorn the records of astronomy for four 
generations and for well-nigh two centuries. Father, 



210 Recent Catholic Astronomers. 

son, grandson and great-grandson, all served France 
at the Paris Observatory, the first, second and fourth 
as its chief director. It is the founder of this dynasty 
of distinguished savants who claims our attention 
here. 

Giovanni Domenico Cassini, for such was his full 
name, was bom near Nice, then Italian soil, in 1625 
and died at Paris in 1712. His long life of eighty- 
seven years was dedicated chiefly to astronomy. 
Not a priest, he was yet a man of profound religious 
belief and of devout habits, teaching for years under 
the direct patronage of the Popes at Rome and 
Bologna, and later ceded by the Holy Father to France 
with utmost reluctance. He had been schooled by 
the Jesuits at Genoa. In his middle years he wrote 
and sent to the Jesuit, Fr. Riccioli, a treatise on the 
Immaculate Conception, and in his last year when 
he had been stricken totally blind he found in religion 
his chief consolation. Many Jesuit fathers, moreover, 
were taught astronomy by him who were afterwards 
to labor on the Chinese Mission. 

Two Periods in His Life. The first half of his life 
was spent in Italy, the second in France. Loaned 
to Louis XIV by the Pope in 1669 when he had just 
reached middle age, he became attached to the soil 
of France, was soon naturalized as a citizen there and 
married a French woman, by whom he had a son, 
the first in a long line of worthy descendants. His 
interest in astronomy dated from early youth. Al- 
ready at nineteen he had become instructor at 
Bologna, where he was destined to abide for twenty - 
five years, for most of that period as chief professor 
of astronomy. 



Recent Catholic Astronomers. 211 

By the year 1669 his fame had reached the ears of 
the French court, chiefly through the report of the 
Abbe Picard, then professor of astronomy at the 
College de France. He was permitted by the Holy 
Father to retire from Italy for a time, though the 
latter was loath to part with his services even temp- 
orarily. Cassini had been of real help to the Holy 
See by reason of his knowledge of both civil and 
military engineering, for his talent was versatile. 
Arrived in France, he prolonged his stay indefinitely 
and gave to the realm of Louis Quatorze the last 
forty-three years of his life. 

Astronomical Achievements. In both countries he 
did astronomical work of brilliant character. As will 
be seen from the appended summary, his labors were 
chiefly observational. The telescope, reinvented by 
Galileo, had now been much perfected, and some of 
the very finest instruments, made by Campaniof Rome, 
were placed in Cassini's hands. 

His first literary production was a treatise on the 
comet of 1652. Soon there followed a series of 
discoveries in planetary astronomy of the first im- 
portance. It may be remembered from a former 
article of this series that one proof for the rotation 
of our earth is found in the axial movement of the sun 
and the planets. It is to Cassini that the world owes 
the first discovery of this important set of truths. 

In 1665 he perceived the rotation of Jupiter, fixing 
its period at 9 hrs., 56 mins. Incidently he observed 
in that year, first of men, the transit of a satellite across 
the face of the planet. A year later he found that 
Mars was rotating with a period of 24 hrs. , 40 mins. 
He was the first also to observe the white polar caps 



212 Recent Catholic Astronomers. 

of the ruddy planet. The rotation or libration of 
Venus, he could not define which, was determined by 
him in the following year as occurring once in every 
23 hrs. Later, in 1678, when he had changed his 
residence to Paris, he was able to detect the sun's 
rotation on its axis in a period of 25.58 days. Cassini 
was, therefore, the pioneer in the study of solar and 
planetary rotations, and his calculations remain even 
now almost mathematically correct. 

His Achievements at Paris. Soon after going to 
Paris, between the years 1670 and 1672, he observed 
and studied the New Star which had blazed forth 
temporarily in the constellation Cygnus and which 
had been first sighted by a Carthusian monk of 
Dijon, Fr. Anthelme. About the same time he made 
in collaboration with Richer the first scientific 
determination of the sun's distance, fixing it at eighty- 
seven millions of miles, which we know now to be 
some six million miles short of the reality. 

Again let it be remarked, however, that it was in the 
field of planetary astronomy that his finest victories 
were won. He will be longest remembered for having 
added a group of four Satumian satellites to the one 
discovered by Huyghens. These "finds," occurring 
between 1671 and 1684, would have been impossible 
without the splendid instruments he had received 
from Campani of Rome. Meantime, in 1675 or 1676, 
he enlarged further our knowledge of the planet 
Saturn, by distinguishing two rings in the annular 
body surrounding the planet, instead of the single 
ring observed already by Galileo and Huyghens. 

We might continue on thus for some paragraphs 
enumerating the successful investigations of this 



Recent Catholic Astronomers. 213 

great astronomer. His studies on atmospheric re- 
fraction, on the Jovian system of satellites and the 
determination of a meridian arc, all important, would 
require each a section for its proper elucidation. Of 
his pioneer work on the Zodiacal Light, pursued from 
1683 to 1688, Todd of Amherst has written that "he 
had established its form and position so critically 
that no observations at the present day would appear 
to indicate any change." 

A Catholic Astronomer. Enough has been said to 
prove that we are here deaHng with an astronomer 
of almost, if not quite, the first rank. Cassini is 
quoted again and again in current text books of 
astronomy. In the temple of the world's greatest 
scientists there is a niche reserved for him. That with 
love of science he combined sincere love for religious 
truth is proof that there is no incompatibility between 
the two. That his career unfolded itself in the years 
just following Galileo's condemnation, under the 
auspices and favor of the Church of Rome, is proof 
that the Catholic Church is not opposed to the proper 
advance of Science. 

FR. PIAZZI. 

The Eighteenth Century. After Cassini came the 
eighteenth century with its race of giant mathe- 
maticians, chiefly French, whose triumph it was to 
apply Newton's law of gravitation successively to all 
the individual bodies of the solar system. So firmly 
did they intrench this all pervading law that there- 
after it had nothing to fear from hostile criticism. 

In this period as in the preceding occur Catholic 
names garlanded with honor. True, its first honors 



214 Recent Catholic Astronomers. 

are by common consent awarded to two who were 
outside the Catholic pale, Herschel of England and 
Laplace of France. But only just behind in celebrity 
come a fair number of loyal Catholics, among them the 
Jesuits, Frs. Boscowich and Mayer. Of peculiar 
interest and of more than ordinary claim to our atten- 
tion is the career of Fr. Piazzi, an Italian priest of the 
Theatine order, who on the night that ushered in the 
nineteenth century discovered the first of the minor 
planets. 

Discovery of Ceres. The discovery of the little 
planet Ceres was one of the many incidents that make 
the history of astronomy so fascinating. It was one 
of the succession of surprises that followed Galileo's 
invention of the telescope. As events proved, it was 
the first in a train of similar revelations, for when the 
first minor planet had been found, the way was opened 
for a long series of similar disclosures reaching to the 
present moment and not yet at an end. 

Ceres is the type of an entire class of celestial 
objects known indifferently as minor planets, planet- 
oids, or asteroids, of a new species and rank, different 
from the many species hitherto catalogued. Sun and 
moon, planets and stars, had been known to men from 
time immemorial. Comets and meteors were transient 
objects almost equally well known. Recently the 
telescope had revealed nebulae distinct from the stars 
and many new moons or satellites attached to the 
various planets. But now under Fr. Piazzi's hand, 
this powerful instrument caused the firmament to 
yield up other secrets, tiny jewels daintily set by the 
Great Artificer in the casket of the heavens. 

Preparation for the Discovery. The story of the 
finding of Ceres runs in some four sections or para- 



Recent Catholic Astronomers. 215 

graphs and brings one back a century or two in 
astronomical history. As early as the year 1600 or 
thereabouts, Kepler had conjectured that there niight 
be an undiscovered planet in the space that inter- 
vened between Mars and Jupiter. The suggestion 
was almost heresy at the time, for a certain sacredness 
was attributed to the number seven as applied to the 
planetary group. Heretical or not, Kepler advanced 
the view of a new planet, unable otherwise to accotmt 
for the disproportionate distance between Mars and 
Jupiter. 

In the next century, two astronomers named 
Titius and Bode confirmed the likelihood of the 
existence of Kepler's supposed planet by working 
out, as they believed, the law of distances according 
to which the planets are arranged in the solar system. 
This law, first formulated in 1772, is sometimes called 
the Law of Titius, sometimes the Law of Bode. It 
says that the planets. Mercury, Venus and the rest, 
are separated from the sun by distances that increase 
in regular arithmetical progression. 

It gives a set of figures simply related, expressing 
approximately the distances of all the planets. By 
adding 4 in turn to the numbers 0, 3, 6, 12, 24, 48, 
96, etc., we obtain the series in question. The figures 
obtained, viz. 4, 7, 10, 16, 28, 52, 100, etc., are found 
to be in the same ratio as the solar distances of Mercury, 
Venus, Earth, and Mars, and skipping the figure 
28, the higher numbers 52 and 100 apply quite well 
to Jupiter and Saturn. 

Indeed, when Herschel in 1781 discovered the great 
planet Uranus, it was found to fall under the number 
196, the next higher number demanded by B ode's 



216 Recent Catholic Astronomers. 

Law. This cumulative testimony made it seem 
probable that there must be as yet unseen a member 
of the group of planets in the space between Mars and 
Jupiter, at the post indicated by the number 28. 
Kepler's conjecture had found reinforcement in the 
Law of Titius or Bode. 

Search for the Planet. There ensued then a search 
for the suspected planet, led by Von Zach of Germany, 
pursued faithfully by him for fifteen years beginning 
in 1785, and finally organized by the same astronomer 
by dividing the Zodiac into six equal parts each 
assigned to a chosen observer, one of his band of 
"celestial police." But, strange to say, the organiza- 
tion had scarcely gotten well to work when announce- 
ment came from another quarter of the discovery for 
which they had been planning. 

To Fr. Piazzi, a Theatine priest laboring in Sicily, 
fell the honor which Von Zach had sought. This 
priest was at the moment diligently employed in 
completing a catalogue of the stars begun ten years 
before. On the opening night of the nineteenth 
century, January 1, 1801, he descried a new object 
in the Zodiac which after six weeks of watching he de- 
termined to be neither comet nor star, but a veritable 
planet with an independent motion around the sun 
as a focal centre. With the single exception of 
Herschel's finding of Uranus in 1781, it was the first 
discovery of a planet since the most ancient times. 

Piazzi at once communicated the news of his 
success to the astronomers of Milan and Berlin. The 
planet was soon lost to view merged in the rays of the 
sun. But it was rediscovered by Von Zach himself 
just a year later, on the night of January 1, 1802. 



Recent Catholic Astronomers. 217 

In Piazzi's honor and at his request, the name Ceres 
was bestowed on the new planet, this being the name 
of the ancient pagan goddess of the fertile island of 
Sicily. In subsequent years some five hundred other 
planetoids have been detected floating in the zone of 
space between Mars and Jupiter. 

Piazzi's General Career. Piazzi's discovery of the 
first minor planet, though partly accidental, was 
37et the just reward of a worthy career spent almost 
entirely in the service of astronomy. Bom in Italy 
in 1746, he had entered at the age of eighteen the 
Theatine order of priests founded by St. Cajetan 
early in the sixteenth century. After teaching for 
a time in Italy and Malta, he became professor of 
mathematics at the University of Palermo in 1780. 
Here the Viceroy of Sicily befriended him, building 
for him a fine observatory in 1791. 

Meantime, from 1786 to 1789, Piazzi was perfecting 
himself in astronomy under Lalande at Paris and 
Maskelyne at Greenwich. From England he brought 
back to Sicily a five-foot circle for measurement, the 
largest and finest instrument of its kind then known. 
It had been built at his express order by Ramsden of 
England. Equipped now with proper instruments, 
he entered upon expert observational work that 
continued for several decades, terminated only by his 
death in 1826. 

Particular Achievements. Besides his finding of 
the new planet, Piazzi is honorably remembered for 
his researches in stellar astronomy. From 1791 
forward, he was engaged upon a catalogue of the 
stars which, when finally published in 1803 and 1814, 
was acknowledged to be the best that had appeared. 



218 Recent Catholic Astronomers. 

Embracing almost 8000 stars, it was constructed on 
a plan that was then regarded as a model. 

A particularly interesting bit of observational 
work was his discovery in 1792 of the proper motion 
of the star numbered 61 Cygni. It was among the 
first demonstrations of the movement of a star among 
its fellows. The amount of this star's motion as seen 
from the earth is but five and two-tenths seconds of 
arc a year. In a thousand years it will have moved 
from its first position about three times the breath of 
the moon. Small in itself, this speed is very large 
as stellar motions go, and ever since Piazzi's time, 
61 Cygni has been known as the Flying Star. 

Numerous other achievements also marked the 
career of this faithful priest-astronomer, but none so 
noteworthy as those just enumerated. They are suffic- 
ient to have won him a place of honor in astronomical 
history. His name will forever be associated with the 
discovery of Ceres, the first asteroid. His example 
is, however, but one among many of Catholic priests 
who in all the centuries have found delight in the study 
of the heavens. 



CHAPTER XXI. 
FR. ANGELO SECCHI, SJ. 

"One of the glories of Italy," such was the en- 
comium paid Fr. Secchi by one of his fellow Itahan 
astronomers shortly after his death in 1878. Sim- 
ilar eulogies were sounded in France, Belgium and 
England. The whole world, irrespective of nation- 
ality or creed, united in mourning his loss and in 
testifying the most sincere respect for his memory. 

Nor had Secchi to wait till death for a recognition 
of his merits. Happily in his case the world rendered 
justice while he was yet alive. Marks of esteem came 
to him from every side, and from sources otherwise 
widely divergent, from princes of the Church and 
rulers of states, from the papal government and from 
emperors, as well as from scientists and scientific 
bodies in every civilized country. 

He was a member of the scientific associations of 
London, Paris, Brussels and Berlin, of St. Petersburg, 
Madrid, Philadelphia and Rio Janeiro, as well as of 
numerous Italian societies. Napoleon III gave him 
the cross of the Legion of Honor, and the Emperor 
of Brazil made him a dignitary of the Order of the 
Golden Rose. Moreover, throughout his life he en- 
joyed the favor and patronage of Pope Pius IX. Ex- 
traordinary must have been the gifts and exceptional 
the achievements of the man who could count so many 
distinguished and eminent admirers. 

219 



220 Fr. Angelo Secchi, SJ. 

Secchi*s Early Years. The birthplace of Fr. Secchi 
was the town of Reggio in Northern Italy, and his 
birth-year was 1818. He had completed almost sixty 
years, therefore, when he succumbed to disease in 
1878. Educated b}/ the Jesuits, he entered their order 
at the age of 15, and already in his teaching as a young 
scholastic betrayed his love and talent for the physical 
sciences. Expelled from Italy with others of his 
order in 1847, he was ordained priest at Stonyhurst 
in England. 

It is very interesting for us Americans to learn that 
he spent the first two years of his priesthood in the 
United States, teaching at Georgetown College. There 
he did his first work in astronomy, became enamored 
of the science, and consecrated to it thenceforth the 
best of his powers. At Georgetown, too, he published 
his first work, on some electrical subject, if we re- 
member aright, issued under the auspices of the 
Smithsonian Institution. 

When in the year 1849 Fr. de Vico died, Secchi was 
appointed his successor as director of the observatory 
of the Roman College. The latter is not to be con- 
founded with the Vatican Observatory which is under 
the immediate authority of the Pope. Both are, 
however, pontifical observatories, and at the present 
moment, as it happens, both are directed by Jesuit 
Fathers, Fr. Hagen, formerly of Georgetown, being 
now at the head of the Vatican Observatory. Secchi's 
post was the charge of the similar establishment 
conducted by the Jesuit Order, and connected with 
their Roman or Gregorian university. Thither he 
repaired from Georgetown in 1850 or thereabouts, 
and there he spent all his remaining years engrossed 



Fr. Angelo Secchi, S.J. 221 

in scientific labors, of whose results he has left 
humanity the fullest possible account. 

Director of the Roman Observatory. His first task 
after assuming the directorship was to relocate and 
re-equip the observatory. On the summit of the 
Church of St. Ignatius at Rome, with its powerful 
foundations, he found the rooms and built the towers 
and domes for housing his instruments. To the six- 
inch telescope already in possession, he added a 
splendid nine-inch Merz refractor and a sidereal clock, 
as well as many magnetic and meteorological instru- 
ments. When in 1859 the principle of the spectro- 
scope was discovered by Kirchhoff , he at once adjusted 
this instrument to his telescopes and became one of the 
world's foremost authorities in the science of spectrum 
analysis. 

That he was able to compass these improvements 
was due in great part to the munificence of Pope 
Pius IX. The Pontifical government was especially 
interested in his meteorological work, and in labors 
that made for the safety and convenience of the people. 
The first time-ball signaling the noon hour was 
established at Rome by Secchi at the instance of the 
Holy Father. On one occasion he was missioned to 
inspect the lighthouses in the pontifical states. 

The edifice constructed by Secchi was of particular 
value to the government because it combined in one 
a well equipped weather bureau and an astronomical 
observatory. Herein was placed, for example, the 
most remarkable of Secchi's inventions, a complex 
instrument for recording automatically and simul- 
taneously the temperature, the barometric pressure, 
the humidity, the rainfall, and the direction and 



222 Fr. Angelo Secchi, SJ. 

velocity of the wind. This ingenious device, named 
by Secchi the meteorograph, was exhibited at the 
Paris Exposition of 1867, and was awarded a prize 
of $20,000. 

Stellar Astronomy. It is impossible within our 
narrow limits to give even a fair idea of Fr. Secchi 's 
manifold astronomical discoveries. Leaving all else 
aside, we must content ourselves with a brief develop- 
ment of two of his more noteworthy achievements, 
bearing respectively on the stars and on the sun. In 
the field of sidereal astronomy he had begun in the 
first decade of his administration a particular and 
original study of double stars and nebulae. The 
second decade witnessed his application of spectroscopy 
to a great multitude of stars. The results were of 
surpassing interest and are still widely quoted. 

According to Miss Gierke, it was Fr. Secchi who in 
1862 began the first spectroscopic survey of the 
heavens. He took for examination some four 
thousand stars. These he catalogued in four distinct 
classes, characterized by four spectral types, the 
members of each class being similarly composed. 

In the first class were Sirius, Vega and all other 
whitish stars, more than one-half the entire number, 
characterized by an abundance of the element 
hydrogen. In the second class were yellowish stars 
of the type of Capella and the Sun, almost as numerous 
and exhibiting the presence of the metals in goodly 
quantity. In the third were placed the reddish stars, 
as Betelgeux and An tares, and the variables, as 
Mira, giving the spectrum of the metalloids. Finally 
there were a few ruby-colored, "like drops of blood," 
whose basis was the spectrum of carbon. Thus did 



Fr. Angelo Secchi, SJ. 223 

Secchi explore those distant orbs trillions of miles 
away, and by bringing them into his laboratory, as 
it were, oblige them to declare the elements of which 
they were composed. 

Solar Astronomy. Even more renowned are Secchi's 
contributions to the science of the sun. For almost 
thirty years he continued his observations of this 
greatest of the lights of heaven, investigating all its 
separate phenomena with unsurpassed and perhaps 
unequalled assiduity and success. Solar eclipses and 
sun spots, the sun's chemical make-up and tempera- 
ture and rotation, the faculae, the chromosphere 
with its hydrogen flames, and the corona, all of these 
were the objects of his study. Familiar with all that 
his predecessors and contemporaries had learned touch- 
ing the solar orb, by his own personal researches he 
augmented and enriched this particular chapter of 
astronomy in every single detail. 

Present at a total solar eclipse in Spain in 1860, 
he secured the first photographs ever taken of the 
sun's outer appendages, its hydrogen flames and its 
corona. Later, when Jannsen had discovered the 
means of securing even in broad daylight spectra 
of these flames and of the chromosphere, Secchi was 
among the first, as he became among the most assidu- 
ous, in applying the new method. One other solar 
eclipse was witnessed by him in 1870, but, as he him- 
self confesses, with less happy results, owing to 
sinister atmospheric conditions. 

On sun spots, their number, size and ever-changing 
phenomena, he became from long experience a world- 
renowned authority. With Faye, one of the most 
eminent of the French astronomers, he disputed 



224 Fr. Angelo Secchi, S.J. 

ardently the question of the origin of sun spots, 
attributing them to solar volcanic eruptions and de- 
nying Faye's theory of solar cyclones or whirlwinds. 

His Literary Productions. Even the unlearned in 
these branches will now appreciate somewhat the 
marvellous character of Secchi's studies relative to the 
sun. To investigate at a distance of ninety-three 
million miles this luminous body hung in space, at 
that forbidding distance to determine its degree of 
heat and its material composition, to penetrate the 
mysteries of its physical life by interpreting the many 
phases of activity it displayed, such were Fr. Secchi's 
crowning accomplishments. Among his numerous 
literary productions, his book entitled Le Soleil, for 
it was written in French, is on all hands acknowledged 
to be his masterpiece. First printed in 1870, then 
enlarged and published in a magnificent edition of two 
volumes in 1875-7, it is regarded as one of the greatest 
astronomical works of the century. 

He published, besides, a half dozen other volumes, 
the latest a work on the Stars, completed and issued 
in his dying year. His minor works, memoirs, 
monographs and essays, issued from his hands at the 
average rate of one a fortnight, for the space of twenty- 
seven years. The catalogue of his complete works 
includes close to seven hundred titles. 

Scholar and Religious. Thus indefatigable and 
thus productive was the immortal Fr. Secchi. He 
has taken his place among the greatest astronomers 
of the age. When after the triumph of Victor 
Emmanuel in 1870 the other Jesuits were expelled 
from Italy, Secchi, with a few attendants, was 
permitted to remain. So highly was his genius rated 
even by the civil powers. 



Fr. Angelo Secchi, S.J. 225 

But he remained forever true to his reHgious vows, 
as estimable in his private life as in his public accom- 
plishments. Of all the eulogies rendered him, un- 
doubtedly none would have given him greater 
pleasure than that of his distinguished patron and 
friend, Pope Pius IX: "Behold the true religious 
and the true Jesuit! So learned and so humble!" 

LATER ASTRONOMERS. 

The influence of Fr. Secchi, the Jesuit astronomer, 
has been widely felt throughout the Catholic world. 
Many members of his own order have followed in the 
footsteps of their distinguished predecessor, with such 
excellent results that the work of the Jesuit observa- 
tories scattered over the globe commands universal 
respect. Others also, outside the Jesuit order, have 
owed to Fr. Secchi the inspiration to devote their lives 
to astronomical and kindred studies. 

Fr. Denza, Barnabite. Among the worthiest of his 
immediate pupils was Fr. Denza, a member of the 
Barnabite order of priests. The latter was, like his 
master, an Italian, and dedicated to his native 
country his entire life-service. He was born at 
Naples in 1834 and died at Rome in 1894. The 
major part of his manhood was spent at the Barna- 
bite College of Moncalieri, near Florence. For thirty- 
four years, from 1856 to 1890, he taught there, 
specializing in meteorology. 

The fame and influence of Fr. Denza reached far 
beyond the boundaries of his college. A monthly 
bulletin of meteorology, published continuously from 
1859 till his death in 1894, made this humble and de- 



226 Fr. Denza. 

vout priest known throughout the length and breadth 
of Italy. It was in imitation of the observatory at 
Moncalieri and through its direct influence that two 
hundred other weather bureaus were set up in various 
parts of Italy. In appreciation of his services, Denza 
was made President of the Italian Meteorological 
Society in 1881, and was continued in this office for 
many years. 

Closely related with meteorology is the science of 
astronomy, for one is the physics of the atmosphere, 
the other the physics of the heavens. It was natural 
that Fr. Denza, like his preceptor Fr. Secchi, should 
combine in his studies these two branches of learning. 
His claim to mention in the present series of brief 
biographical memoirs, rests upon the emphasis he gave 
in his last years to the study of astronomy. 

Embassies to France. Twice he was sent by the 
reigning Pontiff, Leo XIII, as a delegate to scientific 
congresses held in France. After the first of these, in 
1884, he visited England and Holland, and was re- 
ceived in both countries with acclaim and honor. 
On the occasion of his second visit to France in 1887 
he was able to accomplish a very notable stroke in 
favor of the interests he represented. 

At this convention, the Paris Astronomical Congress 
of 1887, it was decided to undertake an international 
photographic survey of the heavens. All the stars 
down to the fourteenth magnitude inclusive were to be 
photographed and properly catalogued. It was a 
gigantic enterprise, and even now awaits its final 
accomplishment. The eighteen observatories among 
which the work was to be apportioned, must evidently 
be of the finest character from the viewpoint of suit- 
ability for this particular line of research. 



Fr. Denza. 227 

It was in consequence of Fr. Denza's influence and 
in direct answer to his appeal, that the Vatican 
Observatory was included among the limited number 
marked with this signal honor. It must surely have 
been gratifying to the scholarly pontiff that such 
recognition was given to the astronomical observatory 
over which he had immediate jurisdiction. 

The Vatican Observatory. The papal observatory, 
established years before, had been developed into a 
new institution under the fostering care of Leo XIII. 
He had given to it for its use the ancient Leonine 
Tower, situated within the precincts of the Vatican. 
He had moreover caused it to be equipped with proper 
instruments. These donations, coupled with a display 
of unflagging personal interest, did honor to the learned 
pontiff, and gave encouragement to the scientists 
appointed to carry on the observatory's work. 

When the first director died in 1890, Fr. Denza was 
quite naturally chosen by the Holy Father for the 
succession. The new appointee remained in charge 
of the observatory's affairs till his demise in 1894. 
During his brief term of office he inaugurated success- 
fully the Vatican's share in the great undertaking of 
photographing the entire heavens. At his death 
he was president of the Academia dei Nuovi Lincei. 
Author of several treatises, he bequeathed to pos- 
terity the example of a sincere love for learning, 
coupled with true devotion to his priestly calling. 

Fr. Denza's successors at the Vatican Observatory 
illustrate the widespread interest of the different 
religious orders in the subject of astronomy. His 
immediate successor was Fr. Rodriguez, a Dominican, 
who occupied the post for twelve years. At his death 



228 Fr. Denza. 

the charge was offered to Fr. George Searle, the 
Paulist, director of the observatory at the Catholic 
University in Washington. He decHning the pro- 
motion, the office was conferred on Fr. Hagen, S.J. 
then stationed at the Georgetown Observatory. 

This Jesuit father, a speciaHst in astronomy and 
author of several volumes of acknowledged value, 
will doubtless bring new fame and glory to his own 
religious order and to the observatory refounded by 
Leo XIII. 

Miss Agnes M. Gierke. We cannot in justice 
terminate this series of memoirs, incomplete though 
it be, without some reference to the Irish Catholic 
lady whose name is written above. No one in modem 
times has written more beautifully on astronomical 
subjects than Miss Agnes M. Gierke. Such was the 
praise given her at the time of her death in 1907 by 
the most impartial critics. Though she had not been 
herself a practical astronomer to any considerable 
extent, she had nevertheless served the science so 
admirably with her pen as to win admission into the 
best of the British astronomical associations. She 
was one of four women who alone, in its long history 
of centuries, have been made Fellows of the Royal 
Astronomical Society. 

The subject of this memoir was born in County 
Cork, Ireland, in 1842, and died at London in 1907. 
Educated privately, she received an excellent training 
in general literature and in music. As early as 1857 
she evinced a more than common interest in astronomy, 
presaging her future career by beginning to write at 
that tender age a history of the science. After spend- 
ing many years in study at Florence, Italy, she 



Miss Gierke. 229 

returned to the British Isles in 1877 and settled at 
London. Her remaining thirty years were a period of 
remarkable literary activity, devoted almost ex- 
clusively to the exposition of astronomical subjects. 

Her Literary Labors. Our space is too short to 
allow an adequate enumeration of her literary pro- 
ductions. She was a regular contributor to the 
Edinburgh Review, her "Copernicus in Italy" of the 
year 1877 being the first of a series of fifty-five articles 
from her pen accepted by that journal. Other 
periodicals, too, were enriched by her astronomical 
essays. 

For the Dictionary of National Biography she wrote 
as many as one hundred biographies of famous 
scientists. If one has occasion to consult the well- 
known Encyclopedia Britannica, one will find many 
of its articles on the world's great astronomers, as 
Galileo, Kepler and Laplace, signed with her initials. 
Unfortunately she lived to write but one article for the 
Catholic Encyclopedia, that on Astronomy. 

More important than this occasional work were the 
half dozen complete volumes, issued from 1885 on 
at fairly regular intervals. Of these we have space to 
mention only her History of Astronomy in the Nine- 
teenth Century. This book, appearing first in 1885, 
established at once the reputation of its author. 
Brought constantly down to date in successive 
editions, it reached its final form in 1902. There 
exists no more authoritative or finer treatise on the 
subject of which it treats. 

Science and Religion. In all of Miss Clerke's 
writing is found the same twofold characteristic of 
charming literary style and profound astronomical 



230 Miss Gierke. 

knowledge. In her power of exposition she is admitted 
to have been almost, if not quite, unrivalled among 
recent authors of astronomical books. That her 
scientific attainments matched her literary gifts, her 
reception into the foremost of Britain's societies of 
science is a proof. 

Fidelity to the faith of her childhood never suffered 
from her pursuit of scientific learning. She "acknowl- 
edged with supreme conviction the insufficiency of 
science to know and predict the possible acts of the 
Divine Power. ' ' Her memory will remain an example 
in the concrete of the perfect harmony between science 
and religion. 



CHAPTER XXII. 

THE NEBULAR HYPOTHESIS. 

In every science there is a certain amount of 
speculation, as well as of information founded on 
ascertained truth. So is it with astronomy. The 
modem era has witnessed a marvellous increase in 
our positive knowledge respecting the heavenly 
bodies. The rotation and revolution of the earth, the 
superior magnitude of the sun, the universality of the 
force of gravitation, are no longer subjects for dis- 
cussion. They and countless similar truths have been 
harvested from the field of speculation into the gran- 
ary of well-established facts. 

Knowledge, however, is fertile and generates con- 
stantly new subjects for speculation. The very 
settlement of ancient astronomical problems by 
modem science has started new problems that whet 
the mental appetite. Modem astronomy, like its 
ancient counterpart, has its own theories and specula- 
tions, attempts to penetrate farther into the unfathom- 
able mystery of nature. Of these modem astronomical 
theories, the most important and interesting is the 
Nebular H}'pothesis. 

Its Purpose. This hypothesis is an attempt to 
explain the manner in which the solar system was 
formed. It has for its purpose to trace the history of 
the solar system from the beginning down to the 

231 



232 The Nebular Hypothesis. 

present time. The past history of the system 
dominated by the sun we cannot, it is true, know 
with certainty. There are no historical records to 
appeal to. We can only infer and conjecture. But 
that our conjecture may have weight, it must rest 
on the present disposition of the bodies of the solar 
system and on the constant laws of nature. 

Such a conjecture is the Nebular Hypothesis, in- 
teresting because of the fundamental import of the 
problem it attempts to solve, and attractive because 
of the beauty of its solution. Of the truth of this 
theory we have not now to speak. Whether or not it 
portrays correctly the evolution of the solar system, 
we do not know for certain and perhaps shall never 
know in this mortal life. But all must admit that it 
is a conception of inherent beauty, leaving an in- 
delible impression on the imagination. Whether we 
subscribe to it or not, we cannot deny it to be a 
bold and daring speculation, worthy of the men of 
genius who were its authors. 

The Solar System. It will be our effort in this 
chapter to expose the Nebular Theory in outline, by 
describing the process through which according to its 
tenets the solar system has reached its present state 
of development. As a preliminary, it will be necessary 
to recall the present disposition of the bodies that are 
involved. 

The solar system is composed chiefly of the sun, 
the planets and their satellites. Minor members, 
which for present purposes need not be heeded, are 
meteors, some comets and the zodiacal light. The 
principal planets are eight in number, named in order 
Mercury, Venus, Earth, Mars, Jupiter, Saturn, 



The Nebular Hypothesis. 233 

Uranus and Neptune. Each of these, with the ex- 
ception of the first two, is known to be accompanied 
by one or more moons or satelHtes. The number of 
these ancillary bodies varies from one for the Earth 
to ten for Saturn, and totals not far from twenty-five. 

The nearest planet, Mercury, is at an average 
distance from the Sun of 36,000,000 miles; the most 
remote, Neptune, is separated from it by 2,800,000,000 
miles. Of such enormous magnitudes are the spaces 
with which astronomy deals. Between Mercury and 
Neptune are situated the remaining planets with a 
fairly regular spacing. We have already told how 
the disproportionate gap between Mars and Jupiter 
led to the discovery of Ceres, the first of five hundred 
minor planets, distinguished from their better- known 
congeners only by inferiority of size. 

The Central Body. All the planets, major and 
minor, revolve about a common centre, the sun. 
The sun is therefore the chief and parent of the system 
not only on account of its pre-eminent magnitude, 
for its mass is 750 times that of all the planets com- 
bined, but also because of its gravitational influence, 
which compels the planets to circle in their present 
orbits. 

Is it the parent body in another and more literal 
sense, namely that the planets are but offshoots from 
it and were once incorporated in its mass? This is 
precisely what the Nebular Hypothesis affirms. 
That the sun, planets, and satellites, formed in the 
beginning but one body, that the planets have in 
course of time been detached from the sun, and the 
satellites in turn from the planets, this is the very 
essence of the Nebular Hypothesis. 



234 The Nebular Hypothesis. 

It follows from the theor}/ that the sun must have 
been at one time of far greater extent than now, 
stretching to the extreme boundaries of the present 
solar system, clear to Neptune's orbit, and compassing, 
therefore, a radius of 2,800,000,000 miles. In this 
original body were included all the elements and 
materials now divided between the sun, the planets 
and the satellites. 

The Primitive Nebula. It is further supposed that 
this gigantic primeval body was heated to a degree 
of temperature beyond our power to imagine. An 
immense, fiery, incandescent mass, composed of glow- 
ing vapors and iridescent gases, such is the picture 
of the beginnings of the solar system as revealed by the 
Nebular Theory. 

To one dwelling outside the sphere of solar in- 
fluence, an occupant, let us say, of some far-distant 
world, the primitive sun might have appeared as 
do the nebulae at the present moment, not as a dis- 
tinctly shining star, but as a cloudy mass of light 
of irregular outline and uneven lustre. The theory 
here discussed is called the Nebular Hypothesis, 
precisely because it supposes that the original sun 
was a nebulous body of irregular boundary and 
chaotic structure. A picture of a nebula, to be found 
in any good text-book of astronomy, will illustrate 
what the sun is supposed to have been in the remote 
past. 

Does not this conception of the origin of our system 
accord fairly well with the description given by the 
Book of Genesis of the first primeval chaos? "In 
the beginning God created the heavens and the earth ; 
and the earth was void and empty. And darkness 



The Nebular Hypothesis. 235 

was upon the face of the deep. And the Spirit of 
God moved over the waters." 

Long before the Nebular Hypothesis was broached 
by astronomers, the poet Milton had in his Paradise 
Lost limned a similar picture of the world's beginning. 
The passage begins, 

"A dark, illimitable mass, without bound. 
Without dimension, where length, breadth and height, 
And time and place are lost. Where eldest night 
And chaos, ancestors of Nature, hold 
Eternal anarchy amid the noise 
Of endless wars." 

How like the modern postulate is the poet's noble 
concluding verse, "Some tumultuous cloud instinct 
with fire and nitre" ! 

Variations in the Hypothesis. We have dwelt thus 
long upon the original supposed condition of the 
solar system, because it is the very kernel of the 
Nebular Hypothesis, and the point of harmony among 
all the variations of this celebrated theory. In ex- 
plaining the development of nature from this first 
chaos to its present well-ordered state, the different 
scientists part company. There are three astronomers 
in particular whose relation to the hypothesis it will 
be useful for us to consider. 

PARTICULAR THEORIES. 

Oftentimes the name ''Kant-Laplace Theory" is 
given to the hypothesis we are now explaining. For 
its two chief founders were Kant, the German philos- 
opher, and Laplace, the French mathematician. Both 
flourished in the closing decades of the eighteenth 



236 The Nebular Hypothesis. 

century. Between them, however, we should insert 
the name of Sir William Herschel of England, a con- 
temporary and no less illustrious advocate. To these 
three men and their respective expositions of the 
theory we now turn our attention. 

The Order of the Solar System. To Immanuel Kant 
belongs the credit of having first conceived the 
Nebular Hypothesis. The order and harmony of 
movement of the several members of the solar system 
formed the basis of his reasoning. We have already 
described how the sun is attended by a colony of planets 
circling about it at different distances. We have now 
to recall that all the planets move about the sun with 
almost absolute imiformity. 

All are revolving about the sun in practically the same 
plane, as so many ships on a level ocean. They keep 
true to that ocean level, never leaping up from it at an 
angle or sinking below its surface. The remotest planets 
follow the same plane as the nearest. When we con- 
sider the many possible planes in which the planets 
might have been set moving we see that their uni- 
formity of orbit cannot be the result of chance or 
accident. The chances, says Sir Robert Ball, would 
be a million to one against it. 

Moreover, all move about the sun in a common 
direction, from west to east, which is the direction 
also of the sun's own rotation. It is as if the sun were 
stretching out a great arm into space, forcing the 
dependent bodies to move in unison with itself. Each 
of the planets, too, rotates on its own axis, and all 
rotate in the same direction. The very satellites of 
the planets revolve and rotate in courses parallel with 
those of the larger bodies. It is this harmony of the 



The Nebular Hypothesis. 237 

planetary motions, this "music of the spheres," that 
has excited the wonder and admiration of all thinking 
men since the time of Pythagoras, the ancient Greek 
philosopher. 

Kant's Theory. It was this harmony of motion that 
Kant attempted to explain. One way of accounting 
for it, to be sure, was to refer it simply to the Fiat 
of the Creator. But might there not be another 
explanation? Might not the present admirable ar- 
rangement of the solar system be due to the operation 
of nature's laws ? To say the latter needs not derogate 
from God's glory. Which is more admirable, to 
create a flower full-blown or to create the seed and 
breathe into it a power by which it shall afterwards 
evolve into trunk and stem and leaf and flower ** 

Kant, therefore, conceived that the present orderly 
arrangement of the universe is the outcome of a 
process of growth. He conceived a time in the distant 
past when sun and planets and satellites were all in- 
volved in a huge fiery mass. Forming then but one 
body, they would all participate in a common motion. 
Herein he detected the origin of the uniform motions 
that the planets now manifest. From this parent 
nebula were destined to be bom the planets and their 
satellites. For some parts of the nebula, denser than 
others, would become centres of attraction around 
which considerable masses of matter might be aggre- 
gated. 

By a law of physics, every body in the fluid state 
assumes the form of a sphere or globe. According to 
this law, the aggregations around attractive centres 
would have formed into globes, and in process of time 
a number of distinct spherical bodies would have 



238 The Nebular Hypothesis. 

replaced the original chaotic mass. But even now 
these separate bodies, though independent and 
distinct, would retain the motion in a common direc- 
tion originally imparted to them. 

Thus by an appeal to the laws of nature did Kant 
explain the orderliness and uniformity of movement 
of the heavenly bodies. Expressed briefly, his argu- 
ment says that all the components of the solar system 
have today a common movement because once they 
formed part of a common body endowed with a rota- 
tory movement. Though separated now into smaller 
units, they still traverse space and circle on axes in 
obedience to the original impulse. Whether or not we 
assent to the theory of Immanuel Kant, we may at 
least acknowledge it to be a noble conception worthy 
of its author and not unworthy of the Creator whose 
visible works it seeks to explain. 

Theory of Herschel. Next after Kant in advocacy 
of a nebular theory comes Sir Wm. Herschel. His 
views, arrived at on independent grounds, are a 
valuable confirmation of Kant's hypothesis. They 
will impress us the more if we remember that in the 
field of pure astronomy Herschel was more of an 
expert than Kant, and is rated, indeed, as one of the 
greatest astronomers of all time. 

Herschel's reasoning in favor of a nebular theory 
rested, not as with Kant on the regularity of planetary 
movements, but on the various classes of nebulae 
and stars that dot the heavens. Pioneer in stellar 
astronomy , he had himself discerned some 2500 nebulae 
distinguished from the true stars by being spread out 
as milky or cloud-like masses of light. Among the 
nebulae he had discovered differences of size and of 



The Nebular Hypothesis. 239 

degree of condensation, which suggested to him that 
they might be arranged in classes. 

Some there were, to quote from Newcomb, "large, 
faint and diffused, in which a process of condensation 
seemed hardl}^ to have begun. Then there were 
smaller and brighter nebulae which had been so far 
condensed that the central parts would soon begin 
to form into stars. There were yet others in which 
stars had actually begun to form. And finallj^ there 
were star clusters in which the condensation was 
complete." 

In these four classes of nebulae, Herschel seemed 
to read the history of the universe. Every nebula 
was on its way to become a star ; ever> star had once 
been a nebula. He could even compare the age«; of 
the nebulae from their degrees of condensation, just 
as from other signs we can compare the ages of the 
trees of a forest. 

Application of His Theory. The nebular theory of 
Herschel may without straining be extended to the 
origin of the solar sytem. Indeed the application 
follows of necessity. For if all the stars have started 
from the condition of nebulae, then our sun, which is 
indubitably a star like all the others that sprinkle 
the sky, our sim, the nearest star, must have been itself 
at one time a nebula. When in the nebular state, it 
must have extended far beyond its present confines, 
including within its mass the materials of all the bodies 
now tributary to it. 

Here, then, we have in outline the hypothesis of 
Sir Wm. Herschel. It is an even bolder and grander 
conception than Kant's, for it intimates not merely 
that our solar system is the offspring of a primitive 



240 The Nebular Hypothesis. 

nebula, but that every star of the millions that exist 
has had a similar origin. Every sun was once, in the 
words of Milton, "a tumultuous cloud, instinct with 
fire and nitre." 



CHAPTER XXIII. 
THE THEORY OF LAPLACE. 

In the year 1796, in a book entitled "Exposition 
of the System of the World," the Marquis de Laplace 
presented and explained his theory of the origin of the 
solar system. The authority of the French astronomer 
was so eminent and his reasoning for the theory so 
plausible, that it continued to retain the favor of 
scientists for the space of a century. Even now it is 
worthy to engage our attention, for in the Laplacian 
theory we have the Nebular Hypothesis in its most 
picturesque form. 

Foundation of His Theory. According to Laplace's 
conception, every planet and satellite had once 
existed as a ring or belt of gaseous substance envelop- 
ing a spherical central body. For a model of his 
imagined primeval universe, he pointed to the planet 
Saturn with its attendant system of satellites and 
rings. 

Around the equator of Saturn lie those wonderful 
rings, three in number, situate in the same plane, like 
three hoops of unequal size one within another. 
Much nearer the planet than its ten satellites, they 
cover a breadth of some forty thousand miles from 
outermost to innermost rim. Only a hundred miles 
in thickness, they are yet held together in their 
annular form by gravitational influence. Were they 

241 



242 The Theory of Laplace. 

rings of gold, they could not preserve their figure more 
faithfully. But they are probably made of some 
substance much more tenuous than gold or other 
metal; they are for the most part clouds of vapor 
carrying innumerable shining particles of solid 
matter. 

How wonderful that this belt of attenuated gases 
and solids should be kept in place by the influence 
of the parent body! Among all the marvels of the 
heavens there is perhaps none quite so astonishing 
as Saturn's system of rings. We were familiar with 
the spectacle of a moon guided in its orbit by the 
attraction of a superior body. And we were prepared 
to find in space satellites wheeling about their greater 
luminaries. But it needed the magnifying aid of 
powerful telescopes to teach us that there could be a 
planet attended by a system of concentric rings. 
The disclosure of Saturn's rings came as a surprise. 
They are still an object of never-ceasing wonder, 
for nowhere in nature do we find their parallel. 

Laplace's Inference. To the mind of Laplace the 
rings of Saturn were not merely a source of wonder, 
they were also an index of the life process through 
which every planet has passed. To him the system 
of rings seemed to have been left in the skies by the 
Creator as a memorial of the transmutations that have 
affected the planetary world. They are the sole 
visible remnant of similar formations occurring in the 
solar system at different periods of its history. Ac- 
cording to Laplace, every planet and subsidiary body 
has appeared in one part of its career as a ring of 
vaporous matter. To understand well this assump- 
tion, we must trace with the great French author the 
genesis and development of the planets. 



The Theory of Laplace. 243 

We have to imagine, then, the primeval sun extend- 
ing far beyond its present boundaries, perhaps as far 
as Mercury's orbit, and around it a fiery atmosphere 
of incredible depth reaching the present path of 
Neptune and filling all the space between. It is in 
this solar atmosphere that the planets are contained 
in embryo. We have to picture the sun rotating 
slowly on its axis. With it rotates the far-spreading 
atmosphere clinging to the central body. Behold the 
original majestic movement from which have sprung 
the planetary courses! 

Detachment of the Planets. At the poles of the sun 
the movement is scarcely perceptible while at the 
equator it reaches its maximum. Around the 
equator, therefore, tends to gather the solar atmosphere, 
which becomes wrapped about it as a huge girdle. 
As times goes on, the sun shrinks in size. Constant 
radiation and loss of heat causes it to contract. And 
as contraction proceeds, rotation becomes perforce 
more rapid. 

The swifter the revolution, the greater the centri- 
fugal tendency at the equator. There comes a time 
when this tendency to separate overcomes the powers 
of attraction and cohesion. The remoter part of the 
solar atmosphere becomes detached from the central 
body and forms into a distinct ring of nebulous matter, 
rotating about the sun and encircling it completely. 
That such a ring could have been sustained in space, 
we know from the actuality of the rings of Saturn. 

As the sun with its clinging atmosphere continues 
to contract, the space is widened between the parent 
body and its tributar>^ ring. Meantime the ring 
has been cooling by the radiation of heat and gaining 



244 The Theory of Laplace. 

in compactness as it cools. If it is everywhere homo- 
geneous and of uniform density it will retain indefi- 
nitely its annular form, and there will eventuate a per- 
manent ring like those of the Satumian system. 

But there will probably be some regions denser than 
others and gifted therefore with superior powers of 
attraction. About these denser portions as centres, 
the material of the ring will gather. The densest of 
all will finally attract all the others, picking them up 
on the way, till all the materials of the ring will have 
congregated to form a single spherical mass. For 
the natural form of fluid bodies is the spherical. The 
annular form has been exchanged for the globular, 
the first true planet has come into being and it will 
begin now its regular periodic journeys of revolution 
around the sun. Thus, according to Laplace, was 
generated the first offspring of the sun, the outermost 
of the planets, the body we now call Neptune. 

Formation of Other Planets. As was bom the 
remotest planet, so also were created the other planets 
in like manner. As the sun continues to contract 
in volume, it will after an interval cast off a second 
ring, and later a third and fourth, in the plane of its 
equator. Each ring of fiery incandescent particles 
will revolve about the primary orb in obedience to its 
original impluse. As it solidifies, some parts will 
become denser than the rest and one densest of all, 
around which latter as a centre will accumulate finally 
the ring's entire mass. 

Thus were to be generated in time the eight major 
planets, each in the beginning a ring cast off from the 
sun, of such great circumference as completely to 
enclose the parent sphere. The group of asteroids. 



The Theory of Laplace. 245 

five hundred in number, in the zone between Mars and 
Jupiter, had a similar origin. But the ring from which 
they originated instead of aggregating about one 
dominant centre, divided itself among many different 
centres, with the result of producing a group of five 
hundred minor planets. 

Creation of the Satellites. The birth of the second- 
ary planets or satellites, the hypothesis of Laplace 
explains by the same chain of reasoning. Let us 
suppose one of the major planets fully formed. Let 
our specimen be preferably one of the largest, as Jupiter, 
the giant of the system. At the point we intercept 
it just turned into a sphere, it is itself a miniature sun, 
voluminous in extent and of gaseous constitution. 
Revolving with increasing rapidity, it will by the same 
laws cast off a ring from its bulging equator, which 
will in due time condense into a small globular body, 
tied to its immediate parent by gravitational action. 

As Jupiter shrinks in size by the certain loss of heat, 
another and again another ring will be formed, which 
will successively condense into satellites, each closer 
to the planet than its predecessor. Seven times has the 
process been repeated in the case of the giant planet. 
When, therefore, we now survey Jupiter through the 
medium of a Yerkes telescope, we discover attendant 
on it a group of seven satellites, revolving in the plane 
of its equator and each circling on an axis. 

The number of satellites thus produced has varied 
in general according to the sizes of the planets, as was 
to be expected. Mercury and Venus have no such 
accompanying body. With the others, the range is 
considerable, from one for our Earth to ten for Saturn. 

An Appreciation. Such in brief is the history of the 
universe as interpreted by Laplace. Whether veri- 



246 The Theory of Laplace. 

table or not, it makes at least an interesting story, and 
one that will linger in the memory. From the prince 
of French astronomers, Tennyson, the prince of Vic- 
torian poets, was not loath to borrow his descrip- 
tion of the world's beginnings: 

"This world was once a fluid haze of light. 
Till toward the centre, set the starry tides 
And eddied into suns, that wheeling cast 
The planets." 

OBJECTIONS TO THE LAPLACIAN THEORY. 

For fifty years from its foundation in 1796 and its 
revision in 1808, the Laplacian theory of the origin of 
the solar system seems to have been universally ac- 
cepted. During the last half century, however, it 
has been subjected to such severe and scorching 
criticism that its specific features have been virtually 
abandoned. In considering the attacks made upon 
it, one ought carefully to distinguish between the 
essence of the Nebular Hypothesis, which says no 
more than that the sun and its cortege of planets 
were once involved in a single huge nebula, and the 
particular process by which Laplace conceived the 
primitive nebula to have condensed into planetary 
globes. Objections to Laplace's annulation theory 
need not necessarily affect the Nebular Hypothesis 
itself. 

First Difficulties Raised. Laplace himself was not 
unaware that his theory was open to criticism. Had 
it been otherwise, he would have called it a law or 
doctrine instead of offering it as a theory. The very 
title, Nebular Hypothesis, connotes a teaching not 



The Theory of Laplace. 247 

yet fully verified or immune from the chance of error. 

Laplace foresaw that against his theory of a ring- 
like nebula the objection might be raised that from 
such a nebula would be begotten globes rotating in a 
contrary direction to the common movement of rev- 
olution. For the inner parts of a given ring destined 
to form a planet would possess in his theory of con- 
traction and acceleration, a higher velocity than the 
outer rim. When condensation occurred, therefore, 
this superior velocit}^ would have determined the 
spinning of the planet in a direction opposite to its 
movement through space. The globe would have 
acted precisely as a ball thrown by a pitcher, twisting 
away from the side of greatest velocity. 

Laplace thought to evade the difficulty by assuming 
a certain degree of consistency in the generating ring, 
and conceiving it to revolve as a unit solid mass. 
The supposition was, however, contradictory to his 
main hypothesis, and could not have given complete 
satisfaction even to its inventor. 

Further Objections. As time progressed, it was 
almost inevitable that other flaws and even seams 
should be discovered in the scheme which Laplace 
had elaborated. In 1861, Babinet suggested the 
grave difficulty that, had the sun condensed from the 
orbit of Neptune to its present diameter, it would have 
gained such acceleration of velocity as now to rotate 
with more than ten thousand times its actual known 
speed. Or, conversely, the stm's present rotation- 
period being conserved, Neptune's period of revolution 
should be ten thousand times longer than observation 
shows to be the fact. 

The difficulty has been recently examined and re- 
approved by Moulton of Chicago. It is outlined by 



248 The Theory of Laplace. 

Miss Gierke in her splendid work, Modern Cosmogonies, 
published in 1905, and appears in the mind of the 
authoress an almost insuperable difficulty to the 
particular process of planetary evolution proposed 
by Laplace. 

It was further objected by Kirkwood in 1869 that 
an attenuated mass such as Laplace had prescribed 
could not possibly have formed into rings, for the 
density of the original nebula was millions of times 
less than that of our atmosphere. How shall such 
a tenuous envelope assume definite ring-shaped 
forms? In 1884, the same critic urged in addition that 
it is the way of nature for rings to form from spheres, 
as meteor swarms, for example, are generated from 
comets, and not vice versa as Laplace's theory had 
postulated. 

Newly-Discovered Facts. The more recent strictures 
on Laplace's celebrated theory are no reproach to the 
inventor, damaging though they maybe to his hypothe- 
sis, for they arise from telescopic discoveries he could 
not possibly have foreseen. According to the terms 
of his theory, no satellite of a planet should revolve 
faster than its primary rotates. Now the inner of the 
two satellites of Mars, which were disclosed at Wash- 
ington in 1877, has been found to revolve in a period 
over three times briefer than the planet's rotation-time. 
The inner ring of Saturn, too, surpasses its primary 
orb in speed of revolution. Both these attendant 
bodies behave recalcitrantly to the demands of 
Laplace's hypothesis. 

Finally it will be remembered that one of the basic 
arguments for the Laplacian theory is that all the 
members of the solar system revolve concomitantly 



The Theory of Laplace. 249 

in an almost common plane and in the same direction. 
In disobedience to this law of supposed universal 
prevalence are now found several objects which depart 
notably from the plane of the ecliptic and pursue a 
course contrary to the general movement. Thus the 
four moons of Uranus rise at an angle of 83 degrees 
from the ecliptic and move retrogressively. The orbit 
of Neptune's single moon is tilted at an angle of 35 
degrees and the movement of this satellite is also 
retrograde. Sir Robert Ball considers this anomalous 
progression of the systems of Uranus and Neptune to 
be the most serious of the objections to the nebular 
theory. Not insuperable, however, for he essays to 
answer it and accomplishes his object with more than 
common skill. 

The latest instance of departure from the law is the 
peculiar behavior of the ninth satellite of Saturn whose 
discovery was announced by Wm. Pickering of 
Harvard in 1899. In disagreement with all its sister 
satellites, some of them near neighbors, it revolves 
clockwise instead of counter-clockwise and thus dis- 
obeys the general orders issued to the members of the 
sun's command. 

Modifications of the Theory. This accumulation of 
difficulties has cast such doubts upon the annular 
theory as to imperil perhaps fatally its chance of 
survival. The beautiful ring-like forms perfect and 
exquisite as the girdles of Saturn, from which the 
multitudes of planets and satellites were supposed 
to have descended, must with regret be put aside in 
future attempts to explain the world's evolution. 
The process of development from an original nebula 
to the existing solar family has followed some other 



250 The Theory of Laplace. 

course than the simple, direct and formal method 
which the genius of Laplace had excogitated. 

SUBSTITUTE THEORIES. 

Already a quarter of a century ago and more there 
began to appear alternative theories, some of the 
nature of revisions, other involving radical departures 
from Laplace's attractive hypothesis. Faye of France, 
for example, while clinging to the thought of an ex- 
pansive solar atmosphere equalling Neptune's orbit 
in its spread, conjectured that the smaller and hence 
nearer planets had aggregated first, instead of the 
outermost planet as the former theory demanded. 
Here was a reversal of the order of the planets' birth. 

In 1879, George H. Darwin built up a strong argu- 
ment to prove that the moon had been torn from the 
earth by some mighty cataclysm, forming immediately 
into a sphere instead of going through the tedious 
stages of annular existence. In 1885, he and Poincare 
of France suggested that direct fission might have 
accomplished the separation of the primitive nebula 
into several distinct orbs. Stellar anaylsis now seems 
to indicate that half the stars have divided in two 
before their final condensation. But while there 
are many binary stars, whose origin has been the 
simple fission which Darwin assigns as the cause of the 
earth-moon system, the stars give no evidence of 
repeated fissions such as would have been required to 
surround the sun with its rich colony of planets. 

Both Faye's and Darwin's theories, disparate as 
they are from Laplace's speculation, are yet Nebular 
Hypotheses, for both assume a nebula to have been 



The Theory of Laplace. 251 

the starting-point of the evolution. Lockyer's sugges- 
tion, advanced in 1887, of a primordial aggregate of 
meteorites is equally a nebular hypothesis, substitut- 
ing merely a meteoritic cloud for Laplace's gaseous 
nebula. 

Most Recent Theories. Within the last dozen years 
speculation as to the mode and manner of the develop- 
ment of the solar realm has been, if possible, more 
rife than ever. With one exception, however, all the 
newer theories are but variations of the Nebular 
Hypothesis. Such was the compromise theory of 
Ligondes, adopted by Sir Robert Ball in 1902 in his 
fine work, The Earth's Beginning. Instead of as- 
suming with Laplace a uniform motion in the aborig- 
inal nebula, they allow an initial motion confused 
to a degree, which later must become harmonious 
through the action of physical laws. They thus 
escape the difficulties arising from the contrary 
movement of certain satellites. 

The planetesimal hypothesis, put forth by Chamber- 
lin of Chicago in 1905, is also professedly a Nebular 
Hypothesis. For the gaseous nebula of Laplace and 
the meteoritic one of Lockyer, he substitutes a nebula 
of multitudinous minute planets already revolving in 
their orbits and destined to aggregate into larger 
globes, the existent units of the solar system. 

An Adverse Theory. The only fiat contradiction to 
this almost unanimous trend of thought appears to be 
the novel opinion published this year (1909) by Prof. 
T. J. J. See of the United States Naval Station at 
Mare Island, California. That the planets, inde- 
pendent from the start, have been captured by the 
sun instead of being evolved from it as its offspring, 



252 The Theory of Laplace. 

such is the bold position of this latest of cosmogonists. 
The verification of this theory would mean, it must 
be confessed, the death-knell of the Nebular Hypoth- 
esis. 

For the moment, however, the suggestion appears 
not only startling but dissonant with the facts. Had 
the sun captured at random its attendant group of 
five hundred planets, it would seem that they ought 
now to be pursuing courses as vagrant and erratic 
as the comets, which enter the solar system from all 
parts of space and traverse highly elliptical orbits. 
This is only a tentative restriction, however, and See's 
hypothesis will receive from scientists the respectful 
attention that his previous scholastic achievements 
have justly merited. 

Present Status of Opinion. There emerges from 
the above discussion the obvious conclusion that 
while the Nebular Hypothesis has been stripped of its 
distinctively Laplacian features, in its naked essence 
it is still favored b)/ the vast majority of those com- 
petent to judge. **It is the nearly unanimous con- 
viction of astronomers," says Chamberlin, "that the 
solar system was evolved in some way from a nebula 
of some form." The kernel of the hypothesis thus 
vouched for, the average reader will be less concerned 
about the precise form of the shell in which it is en- 
cased. But not even the average reader can stand 
unconcerned before the larger problem that yet re- 
mains, whether, namely, the Nebular Hypothesis 
itself has brought us back to the very first beginnings 
of the universe. The problem of the world's actual 
first origin still clamors for solution. 



CHAPTER XXIV. 
THE NEBULAR HYPOTHESIS AND CREATION. 

We have seen that, despite the weaknesses of the 
Nebular Hypothesis, the mass of astronomers still 
cling to it in its essential postulate. In the wake of 
expert advocates have followed many priests inter- 
ested in the science. Thus Fr. Guibert, a Sulpician, 
wrote in 1898: "It is a highly probable hypothesis, 
in favor of which weighty reasons exist." Similar 
endorsement was given it in the American Catholic 
Quarterly for October, 1899, in an article by Fr. 
Cortie, a Jesuit. 

Lest this argument from authority be deemed 
insufficient, it may be opportune to resurvey the 
known facts that lend color to the nebular theory. 
Evidently only a brief r^sum6 will here be possible. 

The Arguments Restated. First, there is still ap- 
parent, notwithstanding exceptional instances, a 
general unanimity of movement among the bodies of 
the solar system, particularly if only the larger 
members be considered. The exceptions to the 
general law affect masses of relatively small account, 
as the satellites of Uranus and Neptune, the ninth 
moon of Saturn, and a small minority of the asteroids. 
The fundamental argument of both Kant and Laplace 
retains even now its substantial value. 

As late as 1905, Miss Gierke phrased as follows her 
estimate of the value of this argument: "Clearly, 

253 



254 The Nebular Hypothesis and Creation. 

the unanimity of planetar}^ motions is no result of 
chance; it represents quite obviously a survival of 
the general swirl of an inchoate mass, occupying 
primitively the whole recognized sphere of solar in- 
fluence. Ambiguities set in only when details come 
to be considered." 

Secondly, present facts all testify that change is the 
order of nature. Nothing is at rest or in a static con- 
dition. From the sun's present enormous activity 
exhibited in sim spots, hydrogen flames, and the 
corona, we must conclude that its present phase is 
only temporary, and that it has in all likelihood worn 
quite another aspect in the distant past. 

Now there exist in the heavens thousands of nebulae 
of unequal degrees of concentration, as Herschel had 
affirmed. Moreover, the stars themselves betray 
various stages of development, the dull red manifest- 
ing greater age than the Sirian or whitish stars. If 
analogies avail, may not the various classes of nebulae 
and stars be rightly taken as a model of the vicissitudes 
through which our sun has passed on the way to its 
present perfection? 

More Recent Arguments. The above basic argu- 
ments of the founders of the hypothesis are today 
reinforced by an array of newly-discovered phenom- 
ena. Spectrum analysis has taught us that the chemi- 
cal constituents of the sun and the earth are the same 
as far as they can be matched. With the doubtful 
exception of coronium, all the thirty-six constituent 
elements of the sun are also localized in the earth. By 
no hypothesis is the identity better explained than 
by community of origin from a single parent body. 

The internal heat of the earth, moreover, seems 
a relic of an earlier state in which our globe was heated 



The Nebular Hypothesis and Creation. 255 

to the degree of incandescence. That the interior 
of the earth is more fervid than the surface, volcanos, 
earthquakes and geysers prove indubitably. It is 
hardly less certain that the earth is slowly parting 
with its heat, distributing it through one or another 
avenue to the colder regions of space. If such loss 
of heat has continued indefinitely through all the 
ages, we are forced by physical law to infer that the 
earth was once a vaporous mass such as the Nebular 
Hypothesis has fancied. 

Finally, there are in the solar world formations of 
most peculiar character which may well be survivals 
of the supposed original nebula. Comets, a part of 
the sun's family, present the appearance of nebulous 
agglomerations, especially when in perihelion. The 
zodiacal light, too, a faint glow stretching from the 
sun to Venus, and the Gegenschein or Counterglow, 
which lies beyond the earth, are possibly the last 
remnants of that thin, attenuated, rarefied, yet 
glowing, nebulous mass from which the Hypothesis 
claims the solar system to have originated. 

A Witness to Current Belief. The actual occurrence 
of nebulous substance within the borders of the solar 
system, is the last of a series of five phenomena cited 
in support of the nebular theory. The others were 
in reverse order, the earth's interior heat, the identical 
composition of earth and sun, the sun's unceasing 
activity indicative of change, and the harmony of 
planetary motions. Massed together and properly 
appraised, they constitute a body of evidence not to 
be despised. 

Their effect on the current belief of scientists may 
be gathered from several passages in Miss Gierke's 



256 The Nebular Hypothesis and Creation. 

Modem Cosmogonies, the last of her published works. 
From her masterly exposition of the subject we beg 
to cull the following quotations: 

"Few, perhaps, any longer believe that planetary 
formation took the precise course laid down for it in 
Laplace's System of the World, but fewer still doubt 
that the entire ambit of the solar system was once 
occupied by an inchoate sun, and that its component 
bodies came into being incidentally to that sun's 
progressive contraction." (P. 31.) 

"Laplace laid down the ground plan of a structure 
likely to maintain its substantial integrity, despite 
innumerable additions and rectifications." (P. 38.) 

"That there was in the beginning a solar nebula all 
are agreed." (P. 82.) However, "the mystery of the 
foretime can never be entirely dissipated." (P. 99.) 

"All the inmates of the heavens, stellar and nebular, 
represent quite evidently the debris of a primitive 
rotating spheroid. Its equator is still marked by the 
galactic annulus, its poles by a double canopy of white 
nebulae." (P. 215.) 

Limitations of Science. In the theory of Cosmic 
Evolution thus generally accepted, we have the 
supreme lesson of Science respecting the origin of the 
universe. In tracing the growth of the solar system 
back to a parent nebula, in ascribing a similar genesis 
to the other suns scattered through space, in tenta- 
tively uniting all the stars and nebulae in an original 
all-embracing mass of all but illimitable extent. 
Science has put forth her supreme effort and has 
arrived at her ultimate goal. 



The Nebular Hypothesis and Creation. 257 

"IN THE BEGINNING." 

But the actual first origin of nature remains for 
Science, and must ever remain, an unfathomable 
mystery. Push back the beginnings as far as she 
may, she cannot reach the starting-point. Beyond 
the earliest hour to which she can turn back the hands 
of time, there loom the shadowy vistas of a limitless 
eternity. 

There are problems absolutely and unattainably 
beyond the farthest reach of physical science, and 
among them is the enigma of the world's conception 
and birth. The step that the Nebular Hypothesis 
has taken brings us no nearer the solution. "There 
is a vital heart of things which (by mere Science) 
we cannot hope to reach." 

Key to the Enigma. Elsewhere must we turn for 
the solution of the mystery. To a higher court must 
we appeal, invoking the decision of metaphysical 
philosophy. The partial, transitory phenomena of 
time can onl}^ be explained by a universal, unchanging 
Force that dwelleth in eternity. In that eternal, 
immutable, un waning Power we must seek the source 
of all that is manifested in the material universe. 
Some source there must exist, and it must be adequate 
to all the effects spread before our senses. 

A great divine energy alone can be assumed as the 
sufficient fount of the world's manifold activities. 
It is a Power of commanding intelligence, for from the 
materials and energies of the universe it has fashioned 
"an imperishable order, an impenetrable splendor." 
It is a living force, for out of it as one of its products 
has eventuated in the progress of time that ultra- 



258 The Nebular Hypothesis and Creation. 

physical power which we call Life, able to bend to its 
own uses the purely material forces of nature. 

It is finally, a conscious and personal force, for we, 
the last products of creation, are endowed with both 
consciousness and personality, assuredly not of our 
own contriving nor within the capacity of a blind 
Cosmos to bestow. In a word, underlying nature 
and alone adequately explaining it, we must admit a 
Divinity such as Christianity teaches, the First Cause 
of inanimate and animate creation, in the present as 
in the past upholding all things by the power of His 
word. 

Reasonableness of Creation. If the acknowledg- 
ment of God is necessary, the parallel acknowledg- 
ment of His creation of the world from nothing is not 
unreasonable. Indeed, though Science cannot under- 
stand Creation, it is almost forced to admit it. 
**Science," says Clerk Maxwell, "is incompetent to 
reason upon the creation of matter itself out of noth- 
ing. We have reached the utmost limit of our faculties 
when we have admitted that because matter cannot 
be eternal and self-existent, it must have been 
created." 

Whatever matter is in itself, it owes all its perfection 
of form and figure, of warmth and light and color, 
of composition and structure, and of movement in 
harmonious orbits, in a word, it owes all its best 
features, so physics informs us, to the continuous 
play of energy. Of all these phenomena, then, divine 
energy can have been the source. 

As to what remains, the cold dark clod, the mist of 
inert lifeless atoms, what impossibility is there that 
this poor formless world-stuff should have been the 



The Nebular Hypothesis and Creation. 259 

product of creation ? All the more in the light of the 
newest physics, which teaches that what we call 
matter is only energy under a special form. If the 
new physics is correct, then it becomes easy even with 
mere reason to find the ultimate origin and first begin- 
ning of the universe, discovering it in the Divine 
Energy by which all other energies have been 
produced. 

The Verdict of Faith. In the beginning God created 
the heavens and the earth and all the furniture thereof. 
Over the primeval chaos hovered the Spirit of God 
evolving order from confusion. "Thought instinct- 
ively pauses, "writes Miss Gierke, "before the vision 
of the symbolical brooding dove." And over all still 
reigns the same governing Providence, whose power 
is sufficient to sustain the harmonies of the solar 
system, the corporeal life of plants and animals, and 
the spiritual life of man. 

It is the verdict of reason, strengthened by the 
confident judgment of faith. It breeds no conflict 
or clash with anything that Science offers, for between 
the Nebular Hypothesis and the dogma of Creation 
there is and can be no contradiction. 



CHAPTER XXV. 
SUMMARY AND CONCLUSION. 

Now that we have reached the end of our journey, 
it may profit us to sum up its results by resurvey- 
ing briefly the territory we have traversed. What 
was the purpose that led us on? What did we find 
to be the character of our path? 

Fulfilment of a Purpose. In the series of studies 
just terminated our avowed purpose has been two- 
fold, to acquaint the reader with the most salient 
teachings of astronomy, and to prove that there 
exists a perfect harmony between this science and 
our holy religion. Our aim was partly informational 
and partly apologetic, to supply a certain amount 
of useful instruction and to defend the Church 
from the charge of hostility to science. Apologet- 
ics necessarily involves a measure of controversy. 
But the element of controversy has been reduced 
to the unavoidable minimum, and effort has been 
made to exclude entirely the controversial tone and 
spirit. Our sole quest has been for truth, the Holy 
Grail of scholastic pursuit. 

In pursuance of our double purpose we have di- 
vided the work into two main parts, overlapping, 
however, at times, and never rigidly exclusive. 
About one-half the chapters deal with purely astro- 
nomical doctrine, the other half with historical 
apologetics. The two parts, about equal in length, 

260 



Summary and Conclusion. 261 

are to be appraised as of equal importance. The 
first or scientific section appeals to all who are in- 
terested in the "natura rerum," the nature of things, 
and what educated person is not? The second or 
historical section addresses its appeal to all who 
find attraction in the intellectual triumphs of the 
past. 

Systematic Astronomy. The particular topics chos- 
en from systematic astronomy, though few numerically 
and of simple character, have been selected advisedly. 
If in dealing with the earth, its shape and twofold 
movement, our treatment has appeared to some too 
elementary, we must protest that we have met many 
college graduates ignorant of the arguments for these 
rudimentary astronomical truths. We have therefore 
spread out at length the proofs of the earth's rotund- 
ity, rotation and revolution in language so simple that 
"he who runs may read." 

The superior magnitude of the sun has been es- 
tablished by reasoning that even the non-mathe- 
matical student could grasp. The sun's physical 
nature has been described, and its unfitness for 
habitation put beyond doubt. 

In the planetary system with its marvelous order 
and regularity was found what seems to us an ever- 
cogent argument for the existence of an intelligent 
God. In view of current interest in the question of 
the habitability of the planets, especially of Mars, 
we have treated this problem at considerable length. 
The result of our inquiry was the probable conclu- 
sion that the planets are not inhabited, and that 
the earth, though not the physical, is still to be 
esteemed the moral centre of the universe. 



262 Summary and Conclusion. 

From the planets we passed in thought to the 
fixed stars, in our summary taking guidance from 
the volume issued in 1902 by Newcomb, the late 
lamented chieftain of American astronomers. Fi- 
nally, the concluding chapters were devoted to a 
consideration of that vastest and sublimest of all 
astronomical theories, the Nebular Hypothesis. 

The complete list, earth, sun, planets, stars, and 
nebular theory, is not exhaustive, but it covers in 
some manner the principal subjects studied in sys- 
tematic astronomy. 

Historical Astronomy. The second set of chapters, 
the historical, has invaded territory seldom ex- 
plored in current manuals. Almost any good text- 
book of the science will be found to supply biog- 
raphies of the world's master-astronomers. Hip- 
parchus and Ptolemy of the ancient time, Copernicus, 
Kepler and Galileo of the Renaissance, and Newton, 
Herschel and Laplace of the modem period, are 
adequately treated in a multitude of books. 

But seldom has the history been written from the 
Catholic point of view. The relations between the 
Bible and astronomy have only recently been studied 
in a scientific manner. In a Catholic history of 
the science the results of these interesting biblical 
researches should hold the first place. But the 
Bible represents only the start of the history. The 
way must be followed into the patristic period, the 
first seven centuries of the Christian era. That 
the Fathers of the Church were not unfriendly to 
astronomical science, is the important lesson this 
period has taught. 

The Middle Ages, hitherto summarily put aside 
as unworthy of consideration, we have sought to 



Summary and Conclusion. 263 

liberate from the darkness in which modern neglect 
had enshrouded them. Entering the Modem Pe- 
riod, we have come upon two changes of vital in- 
terest in the history of the science, both accom- 
plished by members of the Church, the overthrow 
of the Ptolemaic theory by Copernicus, a Catholic 
ecclesiastic, and the reform of the calendar by Pope 
Gregory XIII. 

To the famous Galileo case we have devoted 
many pages, applying the results of the best modern 
criticism to this delicate incident of judicial history. 
Finally, from the large phalanx of astronomers who 
have succeeded Galileo, we have brought into re- 
lief some noted scholars of the Catholic faith, Cassini, 
Piazzi, Secchi, Denza and Gierke, with one exception 
names too little known. Catholics should be made 
aware that these names deserve to be ranked just 
after the immortals of astronomical history. 

The Ultimate Lesson. However treated, system- 
atically or historical^, the science of the heavens 
is barren of its best fruit unless it issues in a fuller, 
deeper faith in the existence and surpassing attri- 
butes of God. On the one side, the unfailing order 
of nature demands an intelligent Providence for 
its present explanation. On the other, the pro- 
cesses of nature traced back into the past conduct 
us finally to a divine Creator, Who has existed from 
the beginning and is Himself uncreated. That 
the nature of the Deity is mysterious and incom- 
prehensible, science and faith agree. Both admit 
that the Supreme Being "dwelleth in light inac- 
cessible." Nevertheless, through His visible pro- 
ductions we are able to catch some mirror-like 



264 Summary and Conclusion. 

glimpse of His perfections. The invisible things of 
God, His eternal power and divinity, are known 
from the visible things which He has made. — ^Rom. 
i, 20. 

With the pantheistic doctrine that God is an Over- 
Soul indistinguishable from the universe, we find, 
even in science, no reason for sympathy. True 
it is that in God "we live and move and have our 
being," as an inspired writer has said. True, He 
pervades the whole universe by His power and pres- 
ence. But the Godhead is a Being apart, possess- 
ing attributes that distinguish Him definitively from 
the works of His creation. In the world as such 
there is no sign of the possession of consciousness 
or personality. It goes on its way blindly, like a 
machine directed by some superior hand. The 
order and marvels manifest in all its separate king- 
doms connote a Superior Independent Being, in- 
telligent and personal, omnipotent and eternal. 

With the psalmist we still aver, "The heavens 
declare the glory of God, and the firmament an- 
nounceth the work of His hands." And with Christ 
our Lord we still proclaim as the first command- 
ment of man's religious life, both now and in the 
future, "Thou shalt love the Lord thy God with 
thy whole heart, with thy whole soul, with all thy 
mind and all thy strength." 



APPENDIX. 



I. TABLE OF APPROXIMATE MEASUREMENTS. 

Sun. Diameter, apparent, ^°; actual, 865,000 miles. 

Volume compared with earth's, 1,300,000. 

Mass compared with earth's, 331,000. 
Moon. Diameter, apparent, ^°; actual, 2,160 miles. 

Average distance from earth, 239,000 miles. 

Period, of revolution, 27J days-; of phases, 29^ days. 



Diameter. 


Av. Distance 


Period of 


from Sun. 


Revolution. 


Mercury, 3,000 Miles 


36,000,000 Miles 


85 Days. 


Venus, 7,700 " 


67,000,000 


225 


Earth, 7,900 " 


93,000,000 " 


365i " 


Mars, 4,200 " 


141,500,000 " 


687 " 


Jupiter, 86,500 " 


483,000,000 


12 years. 


Saturn, 73,000 " 


886,000,000 " 


30 " 


Uranus, * 32,000 " 


1,800,000,000 " 


84 " 


Neptune, ** 35,000 " 


2,800,000,000 " 


165 " 



♦Discovered by Sir Wm. Herschel in 1781. 
♦♦Discovered by Leverrier and Adams in 1846. 



II. ASTRONOMICAL LAWS. 

A. Kepler's Laws of Planetary Motion : 

1. The orbit of each planet is an ellipse, with the sun at 
one focus. 

2. The radius vector of the ellipse, i. e. the line from the 
sun to the planet, describes equal areas in equal times. 

3. The square of a planet's period of revolution is propor- 
tional to the cube of its average distance from the sun. 

Note. — Laws I and II were announced in 1609, Law III 
in 1618. 

265 



266 Appendix. 

Law I corrects the error of Copernicus, who had supposed 
the orbits to be circles. 

Law II explains that, though the planet moves with 
varying speed, there is uniformity in its motion, for its line 
of connection with the sun traverses equal spaces in equal 
times. 

Law III informs us that a planet's revolution -time does 
not increase in the simple ratio of its distance, as if all moved 
with the same velocity ; but according to the square root of 
the cube of the distance, for the velocity diminishes with 
the distance. 

B. Newton's Law of Universal Gravitation : All bodies 
in space attract one another with a force directly propor- 
tional to the product of their masses and inversely propor- 
tional to the square of their distance. 

Note. — This law, announced in 1687, is of the highest im- 
portance, for it reveals the force in nature which makes the 
planets move in the orbits correctly outlined by Kepler. A 
planet of itself would move in a straight line forever. But it 
is drawn into an elliptical orbit by the gravitational power of 
a body of superior mass. Thus the earth draws the moon 
from an otherwise rectilinear path into a closed curvilinear 
orbit about itself as a focus. The sun determines in like 
manner the actual orbits of the earth and of the other primary 
planets. 



INDEX. 



A. 

Advocates of habitability, 78 et sqq. 

Albertus Magnus, 168. 

Ancients, concept of earth's form, 2; of sun, 16; observation 
of sun's motion and path, 37; on nature of heavenly- 
bodies, 67. 

Anthelme, Fr., 212. 

Arabians and astronomy, 165; particular services, 166; lack 
of originality, 166; influence, 167; astrology, 168. 

Arago, habitability of sun, 70, 79. 

Aristotle, physics, 181 et sqq. 

Asteroids, uninhabitable, 84; discovery, 214 et sqq.; num- 
ber, 217. 

Astrology, Hebrews, 135; prevalence, 152 et sqq.; falsity, 
153; Scott's reference, 154; Fathers, 154 et sqq. ; Arabians, 
168; early middle ages, 162; later middle ages, 152, 168. 

B. 
Babinet, 247. 

Babylonia, star-worship, 133, 136. 
Bacon, Roger, lenses, 168. 
Ball, Sir Robert, habitability of planets, 87, 89; middle ages, 

158; nebular hypothesis, 236, 249, 251. 
Bede, St., astronomical treatise, 162. 
Bellarmine, Cardinal, Galileo case, 196. 
Bentley, habitability, 79. 
Boscowich, Fr., S.J., 214. 
Brewster, habitability, 79. 

C. 
Caesar, Julius, calendar, 170 et sqq. 
Calendar, the, Copernicus, 51; Dionysius Exiguus, 159; its 

nature, 171; ancient, 172; Caesar's reform, 172 et sqq.; 

papal interest, 174; Gregory XIII, 174 et sqq. 

267 



268 Index. 

Calendar, Gregorian, reception in Germany, 176, 177; in 
England, 177; in Russia, 178. 

Campbell, variable stars, 108. 

Canals of Mars, 90 et sqq. ; doubling, 96. 

Cassini, Domenico, general career, 209 et sqq.; rotation of 
sun and planets, 211; system of Saturn, 212; zodiacal 
light, 213. 

Cassiodorus, manual of astronomy, 161. 

Catalogue of stars, international, 104, 226. 

Celestial Sphere, daily revolution, 29. 

Ceres, discovery, 214 et sqq. 

Chalmers, habitability, 79. 

Chamberlin, planitesimal theory, 251. 

Choas, primeval, in Genesis, 234; in Milton, 235. 

Church, interest in astronomy, 160. 

Clavius, Fr., S.J., calendar, 174. 

Clerk Maxwell, creation, 258. 

Clerke, Miss A. M., Galileo's proofs of Copernicanism, 65; 
habitability, 87, 88; middle ages, 158; reputation and 
biography, 228; writings, 229; nebular hypothesis, 248, 
253; modem cosmogonies, 256; creation, 259. 

Comets, relation to nebular hypothesis, 255. 

Condemnation of Galileo, common opinions, 189; procedure 
of the times, 190; tribunals, 191; occasion, 192; decisions 
of 1616, 192 et sqq.; books prohibited, 193-4; Bellarmine, 
196; Urban VIII, 197; "The Dialogue," 198; trial and 
sentence, 198 et sqq.; interior convictions, 201; late 
advocacy, 202; respect for superiors, 202; no perjury, 203; 
imprisonment nominal, 204; life at Arcetri, 205; intellec- 
tual labors, 206; death, burial, and monument, 207. 

Congregation of Index, 191; Galileo case, 193; estimate, 195. 

Copernican Theory, how received by Protestants, 53; by 
Catholics, 54; Galileo case, 191; qualified condemnation, 
54, 193. 

Copernicus, for earth's rotation, 26; argument, 29-32; 
for earth's revolution, 38; argument, 39; value, 41; 
importance of his reform, 44 ; biography, 45—55 ; education, 
46; versatility, 47; profession, 48; practice of medicine, 
49; astronomical career, 50; calendar, 51, 174; influence, 
52; book, 52; dedication to Pope, 41, 53; death and 
monuments, 54, 



Index. 269 

Cortie, Fr., S.J., nebular hypothesis, 253. 
Cosmas of Egypt, cosmogony, 148. 

Creation, reasonableness, 2.58; Clerk Maxwell, 258; Miss 
Gierke, 259. 

D. 
Darwin, George, earth-moon theory, 250. 
Denza, Fr., meteorologist, 225; delegate to scientific con- 
gresses, 226; director of Vatican Observatory, 227. 
Design, Argument of, 60, 66, 76, 263. 
Dionysius Exiguus, calendar, 159. 

E. 
Earth, place in astronomy, 1; shape according to ancients, 

2—3; how supported, 4; a sphere, Ptolemy's proofs, 5— 6; 

other proofs, 8—9; medieval doubts, 7, 9—10; size, 13 et sqq. ; 

dependence on sun, 15 et sqq. ; residence of man, 18, 23, 

89, 97, 115; apparent repose, 24; speed of rotation, 25; 

Ptolemy's objection, 26; Copernicus for rotation, 27 et 

sqq.; other arguments, 32 et sqq.; for revolution, 38; 

other arguments, 39 et sqq. ; interior heat, 254. 
Eclipses, lunar, 8; solar, 74 et sqq. 
Ecliptic, 38, 59. 
Equinoxes, 38. 
Eusebius, on astronomy, 150. 

F. 

Faith and Science, 259. 

Fathers of the Church, 145 et sqq.; character of study, 145; 

errors, 148; restrictions, 149; opposition, 150; astrology, 

152 et sqq. 
Faye, sun spots, 224; nebular hypothesis, 250. 
Flammarion, habitability, 80. 
Foucault, pendulum experiment, 33. 

G. 
Galileo, planetary motions, 41 ; argument from Jovian sys- 
tem, 64; discovery of sun spots, 69; birth and education, 
181; discoveries in physics, 183 et sqq. ; reconstruction of 
telescope, 168, 186; telescopic discoveries, 187. 



270 Index. 

Galileo Case, Church's attitude fifty years earlier, 170, 175; 
reception of calendar compared, 178 et sqq. See Con- 
demnation. 

Gerbert, Sylvester II, scholarship, 167. 

God, author of life, 94; of world, 99; existence proved 
philosophically, 257; attributes, 257, 264. 

Gravitation, determining orbits, 45, Appendix II. 

Gregory XIII, reform of calendar, 170, 174. 

Guibert, Fr., nebular hypothesis, 253. 

H. 

Habitability, of sun, 72 et sqq.; of stars, 73, 77, 81; o^ 
planets, 77 et sqq. 

Haeckel, habitability, 80. 

Hagen, Fr., S.J., head of Vatican Observatory, 220, 228. 

Hebrews, Ancient, geography, 3; earth unsupported, 4, 118; 
astronomy, 100; firmament, 119; windows of heaven, 
120; source of rain, 121; waters above firmament, 122; 
classification, 123; sun, 124; moon, 126; calendar and 
feasts, 126; stars and constellations, 127; author of 
firmament, 128; against star-worship, 130 et sqq.; 
lapses into error, 131, 133; against astrology, 135. 

Herschel, Sir Wm., habitability, 70, 79; eminence, 214; 
discovery of Uranus, 215; nebular hypothesis, 238. 

Hindus, concept of earth's support, 4, 119. 

I. 

Isidore, St. of Seville, value of astronomy, 161. 

J. 

Jannsen, daylight spectra of sun, 223. 

Jesuits in astronomy, 209. 

Josue, Miracle of, 137 et sqq.; popular view, 138; true 

miracle, 139; a quotation, 140; critical interpretations, 

141 et sqq. 
Jupiter, brightness, 62; bands, 62; satellites, 62 et sqq.; 

rotation period, 211. 

K. 
Kant, nebular hypothesis, 237. 



Index. 271 

Kepler, orbits of planets, 41, 42; habitability, 79; astrology, 
153; Gregorian Calendar, 177; book condemned, 194; 
surmise of new planet, 215; laws, Appendix II. 

Kirchhoff, spectrum analysis, 221. 

Kirkwood, nebular hypothesis, 248. 



Laplace, habitability, 79 ; eminence, 214; nebular hypothesis, 
241 etsqq. ; its basis, 241; development, 243; objections, 
246; present status, 249. 

Law of Titius and Bode, 215. 

Leo XIII, Vatican Observatory, 227. 

Life, abundance, 21; materials needed, 83; atmosphere; 
83; moisture, 84; temperature, 85; origin, 94; require- 
ments in general, 115. 

Light, value, 16 et sqq. 

Ligondes, nebular hypothesis, 251. 

Lockyer, meteoritic hypothesis, 251. 

Lowell, Percival, habitability, 80, 86; Mars, 91 et sqq.; 
origin of life, 94 et sqq. ; temporary stars, 107. 

M. 
Magellan, 7, 9. 

Man, his superiority of nature, 23, 105. 
Mars, habitability, 89 et sqq. ; physical features, 92 et sqq. ; 

probably habitable, 93; inhabited? 94; vegetation, 95; 

no evidence of human life, 95 et sqq.; rotation period, 

211; satellites, 248. 
Maunder, Bible, 117, 121; Astarte, 131; miracle of Josue, 

141 et sqq. 
Mayer, Fr., SJ., 214. 
Mercury, uninhabitable, 84, 87. 

Middle Ages, 158 et sqq.; astronomy in the schools, 159. 
Minucius Felix, argument of design, 61. 
Mitchell, habitability, 79. 
Moon, motion, 35; uninhabitable, 85; measurements, 

Appendix I. 
Moreux, Abb6, 104. 
Motion, not self-revealing, 27. 



272 Index. 

N. 

Nature of heavenly bodies, 67. 

Nebulae, classes, 238. 

Nebular Hypothesis, 79; purpose, 231; essence, 232 et sqq.; 
Kant's theory, 236; Herschel's, 238; Laplace's, 241 et 
sqq.; objections, 246 et sqq.; Faye's, 250; other substi- 
tutes, 250—1; standing arguments, 253; present status, 
252, 256. 

Neptune, satellite, 249. 

New Stars, 106; attempts to explain, 107. 

Newcomb, habitability of Mars, 113; of stellar planets, 112, 
116; quoted, 239; stars, 262. 

Newton, Sir Isaac, law of gravitation, 42, 213, 233, Appendix 
II; habitability, 79; the spectrum, 105. 

Nicholas de Cusa, Cardinal, 169. 

O. 
Outer Planets, uninhabitable, 86. 

P. 

Pantheism, unacceptable, 264. 

Phenicians, star-worship, 132. 

Piazzi, Fr., 213; discovery of Ceres, 214 et sqq.; general 
career, 217; star catalogue, 217; the "flying star," 218. 

Picard, Abbe, 211. 

Pickering, Wm., vegetation on moon, 84; Martian canals, 97. 

Pius IX, patronage of vSecchi, 219, 221. 

Planets, rotation, 32; independent motion, 35; revolution, 
43; distinguished from stars, 56; arrangement, 57; common 
plane, 58; common direction, 59; measurements. Appen- 
dix I; laws of Kepler and Newton, Appendix II. 

Poincar€, nebular hypothesis, 250. 

Proctor, habitability, 80. 

Ptolemy, earth's shape, 5 et sqq.; against earth's rotation, 
26; sun's motion, 38; the Almagest, 38, 167, 168. 

Purpose of celestial bodies, 80. 

R. 

Regiomontanus, 169, 174. 

Rings of Saturn, 212. 241; revolution, 248. 



Index. 273 

Rodriguez, Fr., 227. 

Roman Observatory, 220. 

Romans, Ancient, relation to physical science, 147, 164. 

S. 
Satellites, common movement, 60; uninhabitable, 83. 
Satellites of Jupiter, 62 ; harmony of movement, 63 ; discovery 

by Galileo, 64, 187. 
Saturn, discovery of moons and rings, 212; relation to 

nebular hypothesis, 241 ; ninth satellite, 249. 
Schiaparelli, Martian canals, 90, 97; Old Testament, 117, 

121; Hebrews and star-worship, 134, 135; miracle of 

Josue, 141. 
Science, its limitations, 256. 
Searle, Fr., 228. 
Secchi, Fr., S.J., Copernicanism in Galileo's time, 65; spectrum 

analysis, 71, 106, 222; honors, 219; general career, 220; 

at Georgetown, 220; observatory, 221; meteorology, 

221; stellar astronomy, 222; solar astronomy, 223; 

literary labors, 224. 
See, T. J. J., formation of solar system, 251. 
Solar System, composition and size, 232; centre, 233; order, 

236. 
Spain, astronomy in later middle ages, 165, 167. 
Spectrum analysis, 71, 105, 222. 
Spontaneous generation, 94. 
Stars, uninhabitable, 72, 77, 114; symbols of repose, 100; 

of eternity, 101; distances, 30, 102; size, 30, 103; mag- 
nitudes, 103; number, 30, 104; service to man, 104; 

composition, 105; special types, 105 et sqq. ; purpose. 111. 
Star -Worship, 130 et sqq. 
Stellar Planets, uninhabitable, 110 et sqq. 
Sun, apparent size, 12; ancient concept of nature, 16; light, 

16 et sqq.; heat, 19; sustenance of life, 20; superiority 

over earth, 22; diameter and volume, 22, Appendix I; 

independent motion and path, 35 et sqq.; chemistry, 71; 

habitability, 72 et sqq. ; temperature, 73 ; eclipses, 74 

et sqq.; chromosphere, 75; corona, 75; true nature, 76; 

rotation, 212; distance, 212, Appendix I; dominant 

over planets, 233. 



274 Index. 

Sun Spots, 69; size, frequency, and activity, 74; theories of 

their nature, 223. 

T. 
Telescope, invention and first use, 68, 168, 186. 
Tennyson, quoted, 246. 
Thomas a Kempis, 152. 
Tycho Brahe, planets' orbits, 41; habitabihty, 79; New Star, 

107. 

U. 
Unity, of nature, 72: of sidereal system, 109. 
Uranus, discovery, 215; satellites, 249. 
Urban VIII, relations with Galileo, 197. 

V. 

Variable Stars, 108. 
Vatican Observatory, 104, 220, 227. 
Venus, phases, 42; uninhabitable, 88. 
Vico, Fr. de, SJ., 220. 

W. 
White, Andrew D., Copernicus, 52; Hebrew cosmography, 

120; the Fathers, 145 et sqq.; neglect of patristic writings 

on astrology, 157; Bellarmine, 196. 
Wilson, habitability of sun, 69. 

X. 

Xenophanes, size of earth, 118. 

Z. 

Zach, von, search for planet, 216. 
Zodiac, 37, 58. 

Zodiacal Light, Cassini's studies, 213; nebular hypothesis, 
255. 



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